Agilent Technologies U2000 Series Manual 

U2000 Series Programming Guide Notices © Agilent Technologies, Inc. 2007 No part of this manual may be reproduced in any form or by any means (including elec- tronic storage and retrieval or translation into a foreign language) without prior agree- ment and written consent from Agilent Technologies, Inc. as governed by United States and international copyright laws. Manual Part Number U2000-90411 Edition Second Edition, October 17, 2007 Printed in Malaysia Agilent Technologies, Inc. 3501 Stevens Creek Blvd. Santa Clara, CA 95052 USA Warranty The material contained in this docu- ment is provided “as is,” and is sub- ject to being changed, without notice, in future editions. Further, to the max- imum extent permitted by applicable law, Agilent disclaims all warranties, either express or implied, with regard to this manual and any information contained herein, including but not limited to the implied warranties of merchantability and fitness for a par- ticular purpose. Agilent shall not be liable for errors or for incidental or consequential damages in connec- tion with the furnishing, use, or per- formance of this document or of any information contained herein. Should Agilent and the user have a separate written agreement with warranty terms covering the material in this document that conflict with these terms, the warranty terms in the sep- arate agreement shall control. Technology Licenses The hardware and/or software described in this document are furnished under a license and may be used or copied only in accor- dance with the terms of such license. Restricted Rights Legend U.S. Government Restricted Rights. Soft- ware and technical data rights granted to the federal government include only those rights customarily provided to end user cus- tomers. Agilent provides this customary commercial license in Software and techni- cal data pursuant to FAR 12.211 (Technical Data) and 12.212 (Computer Software) and, for the Department of Defense, DFARS 252.227-7015 (Technical Data - Commercial Items) and DFARS 227.7202-3 (Rights in Commercial Computer Software or Com- puter Software Documentation). Safety Notices CAUTION A CAUTION notice denotes a haz- ard. It calls attention to an operat- ing procedure, practice, or the like that, if not correctly performed or adhered to, could result in damage to the product or loss of important data. Do not proceed beyond a CAUTION notice until the indicated conditions are fully understood and met. WARNING A WARNING notice denotes a hazard. It calls attention to an operating procedure, practice, or the like that, if not correctly per- formed or adhered to, could result in personal injury or death. Do not proceed beyond a WARNING notice until the indicated condi- tions are fully understood and met.

iii General Warranty The material contained in this document is provided “as is,” and is subject to being changed, without notice, in future editions. Further, to the maximum extent permitted by applicable law, Agilent disclaims all warranties, either express or implied with regard to this manual and any information contained herein, including but not limited to the implied warranties of merchantability and fitness for a particular purpose. Agilent shall not be liable for errors or for incidental or consequential damages in connection with the furnishing, use, or performance of this document or any information contained herein. Should Agilent and the user have a separate written agreement with warranty terms covering the material in this document that conflict with these terms, the warranty terms in the separate agreement shall control. Duration and conditions of warranty for this product may be superseded when the product is integrated into (becomes a part of) other Agilent products. During the warranty period, Agilent will, at its option, either repair or replace products which prove to be defective. The warranty period begins on the date of delivery or on the date of installation if installed by Agilent. Restricted Rights Legend The Software and Documentation have been developed entirely at private expense. They are delivered and licensed as “commercial computer software” as defined in DFARS 252.227-7013 (Oct 1988), DFARS 252.211-7015 (May 1991), or DFARS 252.227-7014 (Jun 1995), as a “commercial item” as defined in FAR 2.101(a), or as “restricted computer software” as defined in FAR 52.227-19 (Jun 1987) (or any equivalent agency regulation or contract clause), whichever is applicable. You have only those rights provided for such Software and Documentation by the applicable FAR or DFARS clause or the Agilent standard software agreement for the product involved.

Equipment Operation Warnings and Cautions This guide uses warnings and cautions to denote hazards. Personal Safety Considerations This is a Safety Class I product (provided with a protective earthing ground incorporated in the power cord). The mains plug shall only be inserted in a socket outlet provided with a protective earth contact. Any interruption of the protective conductor, inside or outside the instrument, is likely to make the instrument dangerous. Intentional interruption is prohibited. If this instrument is not used as specified, the protection provided by the equipment could be impaired. This instrument must be used in a normal condition (in which all means of protection are intact) only. No operator serviceable parts inside. Refer servicing to qualified personnel. To prevent electrical shock, do not remove covers. For continued protection against fire hazard, replace the line fuse(s) only with fuses of the same type and rating (for example, normal blow, time delay, etc.). The use of other fuses or material is prohibited. WARNING A WARNING notice denotes a hazard. It calls attention to an operating procedure, practice, or the like that, if not correctly performed or adhered to, could result in personal injury or loss of life. Do not proceed beyond a WARNING notice until the indicated conditions are fully understood and met. CAUTION A CAUTION notice denotes a hazard. It calls attention to an operating procedure, practice, or the like that, if not correctly performed or adhered to, could result in damage to the product or loss of important data. Do not proceed beyond a CAUTION notice until the indicated conditions are fully understood and met.

v General Safety Considerations The following general safety precautions must be observed during all phases of operation of this instrument. Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design, manufacture, and intended use of the instrument. Agilent Technologies, Inc. assumes no liability for the customer’s failure to comply with these requirements. User Environment This instrument is designed for indoor use only. WARNING BEFORE CONNECTING THE POWER SENSOR TO OTHER INSTRUMENTS ensure that all instruments are connected to the protective (earth) ground. Any interruption of the protective earth grounding will cause a potential shock hazard that could result in personal injury. CAUTION • Use the device with the cables provided. • Repair or service that is not covered in this manual should only be performed by qualified personnels.

In This Guide ... 1 Power Sensor Remote Operation Chapter 1 describes the parameters that configure the power sensor and helps you determine settings to optimize performance. 2 MEASurement Commands Chapter 2 explains how to use the MEASure group of instructions to acquire data using a set of high level instructions. 3 CALCulate Subsystem Chapter 3 explains how the CALCulate subsystem is used to perform post acquisition data processing. 4 CALibration Subsystem Chapter 4 explains how the CALibration command subsystem is used to zero and calibrate the power sensor. 5 FORMat Subsystem Chapter 5 explains how the FORMat subsystem is used to set a data format for transferring numeric information. 6 MEMory Subsystem Chapter 6 explains how the MEMory command subsystem is used to create, edit and review sensor calibration tables. 7 SENSe Subsystem Chapter 6 explains how the SENSe command subsystem directly affects device specific settings that are used to make measurements. 8 SERVice Subsystem Chapter 6 explains how the SERVice command subsystem is used to obtain and set information useful for servicing the power sensor. 9 STATus Subsystem Chapter 7 explains how the STATus command subsystem enables you to examine the status of the power sensor by monitoring the “Device Status Register”, “Operation Status Register” and the “Questionable Status Register”. 10 SYSTem Subsystem Chapter 8 explains how the SYSTem command subsystem is used to return error numbers and messages from the power sensor, preset the power sensor, and query the SCPI version. 11 TRIGger Subsystem Chapter 9 explains how the TRIGger command subsystem is used to synchronize device actions with events.

vii 12 UNIT Subsystem Chapter 10 explains how the UNIT command subsystem is used to set the power sensor measurement units to Watts and % (linear), or dBm and dB (logarithmic). 13 IEEE 488.2 Command Reference Chapter 11 explains how the SERVice command subsystem is used to obtain and set information useful for servicing the power sensor.

ix List of Figures List of Figures Figure 1-1 Frequency Dependent Offset Tables 18 Figure 1-2 Typical averaged readings on U2000 Series USB power sensors 25 Figure 1-3 Averaging Range Hysteresis 25 Figure 1-4 Limits Checking Results 28 Figure 1-5 How Measurement are Calculated 35 Figure 1-6 Generalized Status Register Model 37 Figure 1-7 Typical Status Register Bit Changes 38 Figure 1-8 Status System 40 Figure 1-9 Hierarchical structure of SCPI 52 Figure 1-10 Format of 55 Figure 1-11 Format of 57 Figure 1-12 Format of 58 Figure 1-13 Format of 58 Figure 1-14 Format of 59 Figure 1-15 Format of 60 Figure 2-1 Measurement Display CALCulate Block Window 67 Figure 3-1 Measurement Display CALCulate Block Window 84 Figure 3-2 CALCulate Block 84 Figure 7-1 Example of Averaged Readings 166 Figure 10-1 IEEE 488.2 Arbitrary Block Program Data Format 256 Figure 12-1 Measurement Display UNIT Block Window 292

List of Tables List of Tables Table 1-1 MEASure? and CONFigure Preset States 7 Table 1-2 Range of Values for Measurement Limits 29 Table 1-3 Bit Definitions - Status Byte Register 41 Table 1-4 Bit Definitions - Standard Event Register 42 Table 1-5 Bit Definitions - Questionable Status Registers 44 Table 1-6 Bit change conditions for Questionable Status Register 44 Table 1-7 Bit Definitions - Operation Status 45 Table 1-8 Bit change conditions for Operation Status 46 Table 1-9 Bit Definitions - Device Status Register 47 Table 1-10 Bit change conditions for Device Status Register 48 Table 6-1 Frequency and Offset Factor List 148 Table 6-2 Frequency and Offset Factor List 152 Table 9-1 Commands and events affecting Status Register 224 Table 10-1 DEFault: Power Sensor Presets 258 Table 12-1 Measurement Display UNIT Block Window 292 Table 13-1 *ESE Mapping 298 Table 13-2 *ESR? Mapping 300 Table 13-3 *SRE Mapping 307 Table 13-4 *STB? Mapping 309

xi Contents Contents Notices ii General Warranty iii Restricted Rights Legend iii Equipment Operation iv General Safety Considerations v User Environment v In This Guide ... vi List of Figures ix List of Tables x 1 Power Sensor Remote Operation Introduction 3 Configuring the Remote Interface 4 • Interface Selection 4 • USB Configuration 4 Zeroing and Calibrating the U2000 Series USB Power Sensors 5 • Zeroing 5 • Calibration 5 Making Measurement 7 • Using MEASure? 8 • Using the CONFigure Command 10 • Using the Lower Level Commands 15 Using Frequency Dependent Offset Tables 17 • Overview 17 • Selecting a Frequency Dependent Offset Table 22 • Enabling a Frequency Dependent Offset Table 22 • Making the Measurement 22 Setting the Range and Averaging 24 • Averaging 24 • Auto Averaging Mode 24 • Filter Length 26 • Range 26 Setting Offsets 27 • Channel Offsets 27

Contents Setting Measurement Limits 28 • Setting Limits 28 • Checking for Limit Failures 29 Getting the Best Speed Performance 31 • Measurement Rate 31 • Trigger Mode 31 • Output Format 33 • Units 33 • Command Used 33 • Fast Mode 34 How Measurements are Calculated 35 Status Reporting 36 • The General Status Register Model 36 • The Condition Polling Method 39 • Status Registers 39 • Device Status Register 47 • Using the Operation Complete Commands 49 Saving and Recalling Power Sensor Configurations 50 • How to Save and Recall a Configuration 50 Using Device Clear to Halt Measurements 51 An Introduction to the SCPI Language 52 • Mnemonic Forms 52 • Using a Colon (:) 52 • Using a Semicolon (;) 53 • Using a Comma (,) 53 • Using Whitespace 53 • Using “?” Commands 53 • Using “*” Commands 54 • Syntax Conventions 54 • Syntax Diagram Conventions 54 • SCPI Data Types 55 • Input Message Terminators 61 SCPI Compliance Information 62 Summary of Commands 63

xiii Contents 2 MEASurement Commands MEASurement Commands 66 CONFigure[1]? 69 CONFigure [1] Commands 71 CONFigure[1][:SCALar][:POWer:AC] [[,[,]]] 72 FETCh[1]? 74 FETCh[1][:SCALar][:POWer:AC]? [[,[,]]] 75 READ[1] Commands 77 READ[1][:SCALar][:POWer:AC]? [[,[,]]] 78 MEASure[1] Commands 80 MEASure[1][:SCALar][:POWer:AC]? [[,[,]]] 81 3 CALCulate Subsystem CALCulate Subsystem 84 CALCulate[1]:FEED[1] 86 CALCulate[1]:LIMit Commands 89 CALCulate[1]:LIMit:CLEar:AUTo |ONCE 90 CALCulate[1]:LIMit:CLEar[:IMMediate] 92 CALCulate[1]:LIMit:FAIL? 93 CALCulate[1]:LIMit:FCOunt? 94 CALCulate[1]:LIMit:LOWer[:DATA] 96 CALCulate[1]:LIMit:UPPer[:DATA] 98 CALCulate[1]:LIMit:STATe 101 CALCulate[1]:MATH Commands 103 CALCulate[1]:MATH[:EXPRession] 104 CALCulate[1]:MATH[:EXPRession]:CATalog? 106 4 CALibration Subsystem CALibration Subsystem 108 CALibration[1][:ALL] 109 CALibration[1][:ALL]? 110 CALibration[1]:AUTO [ONCE|ON|OFF|0|1] 112 CALibration:ZERO:AUTO [ONCE|ON|OFF|0|1] 114 CALibration[1]:ZERO:TYPE 116

Contents 5 FORMat Subsystem FORMat Subsystem 120 FORMat[:READings]:BORDer 121 FORMat[:READings][:DATA] 123 6 MEMory Subsystem MEMory Subsystem 126 MEMory:CATalog Commands 128 MEMory:CATalog[:ALL]? 129 MEMory:CATalog:STATe? 131 MEMory:CATalog:TABLe? 132 MEMory:CLEar Commands 134 MEMory:CLEar[:NAME] 135 MEMory:CLEar:TABle 137 MEMory:FREE Commands 138 MEMory:FREE[:ALL]? 139 MEMory:FREE:STATe? 140 MEMory:FREE:TABLe? 141 MEMory:NSTates? 142 MEMory:STATe Commands 143 MEMory:STATe:CATalog? 144 MEMory:STATe:DEFine , 145 MEMory:TABLe Commands 147 MEMory:TABLe:FREQuency {,} 148 MEMory:TABLe:FREQuency:POINts? 151 MEMory:TABLe:GAIN[:MAGNitude] {,} 152 MEMory:TABLe:GAIN[:MAGNitude]:POINts? 155 MEMory:TABLe:MOVE , 156 MEMory:TABLe:SELect 158 7 SENSe Subsystem [SENSe] Subsystem 160 SENSe[1]:AVERage Commands 162 SENSe[1]:AVERage:COUNt 163 SENSe[1]:AVERage:COUNt:AUTO 166

xv Contents SENSe[1]:AVERage:SDETect 169 SENSe[1]:AVERage[:STATe] 171 SENSe[1]:CORRection:CSET[2]Commands 173 SENSe[1]:CORRection:CSET[2][:SELect] 174 SENSe[1]:CORRection:CSET[2]:STATe 176 [SENSe[1]]:CORRection:DCYCle|GAIN3[:INPut][:MAGNitude] 178 [SENSe[1]]:CORRection:DCYCle|GAIN3:STATe 181 [SENSe[1]]:CORRection:FDOFfset|GAIN4[:INPut][:MAGNitude]? 183 [SENSe[1]]:CORRection:GAIN2 Commands 184 [SENSe[1]]:CORRection:GAIN2:STATe 185 [SENSe[1]]|SENSe2:CORRection:GAIN2[:INPut] [:MAGNitude] 187 SENSe[1]:DETector:FUNCtion 190 SENSe[1]:FREQuency[:CW|:FIXed] 192 SENSe[1]:MRATe 195 SENSe[1]:POWer:AC:RANGe 198 SENSe[1]:POWer:AC:RANGe:AUTO 200 SENSe[1]:TEMPerature? 202 8 SERVice Subsystem SERVice Subsystem 203 SERVice:BIST:TRIGger:LEVel:STATe? 205 SERVice:OPTion 206 SERVice:SENSor[1]:CDATe? 207 SERVice:SENSor[1]:CDUEdate <“date”> 208 SERVice:SENSor[1]:CPLace <“place”> 209 SERVice:SENSor[1]:FREQuency:MAXimum? 211 SERVice:SENSor[1]:FREQuency:MINimum? 212 SERVice:SENSor[1]:POWer:AVERage:MAXimum? 213 SERVice:SENSor[1]:POWer:USABle:MAXimum? 214 SERVice:SENSor[1]:POWer:USABle:MINimum? 215 SERVice:SENSor[1]:RADC? 216 SERVice:SENSor[1]:SNUMber <“serial_number”> 217 SERVice:SENSor[1]:TNUMber <“tracking_number”> 218 SERVice:SENSor[1]:TYPE? 219 SERVice:SNUMber 220

Contents SERVice:VERSion:PROCessor 221 SERVice:VERSion:SYSTem 223 9 STATus Subsystem STATus Subsystem 224 Status Register Set Commands 226 Device Status Register Sets 231 Operation Register Sets 232 STATus:OPERation 233 STATus:OPERation:CALibrating[:SUMMary] 234 STATus:OPERation:LLFail[:SUMMary] 235 STATus:OPERation:MEASuring[:SUMMary] 236 STATus:OPERation:SENSe[:SUMMary] 237 STATus:OPERation:TRIGger[:SUMMary] 238 STATus:OPERation:ULFail[:SUMMary] 239 STATus:PRESet 240 Questionable Register Sets 241 STATus:QUEStionable 242 STATus:QUEStionable:CALibration[:SUMMary] 243 STATus:QUEStionable:POWer[:SUMMary] 244 10 SYSTem Subsystem SYSTem Subsystem 248 SYSTem:ERRor? 249 SYSTem:HELP:HEADers? 256 SYSTem:PRESet 257 SYSTem:VERSion? 260 11 TRIGger Subsystem TRIGger Subsystem 262 ABORt[1] 263 INITiate Commands 264 INITiate[1]:CONTinuous 265 INITiate[1][:IMMediate] 267 INITiate:CONTinuous:ALL 268

xvii Contents INITiate[1]:CONTinuous:SEQuence[1] 270 INITiate[1][:IMMediate]:ALL 272 INITiate[1][:IMMediate]:SEQuence[1] 273 TRIGger Commands 274 TRIGger[1]:DELay:AUTO 275 TRIGger[1][:IMMediate] 277 TRIGger[1]:SOURce BUS|EXTernal|HOLD|IMMediate 278 TRIGger[:SEQuence]:SLOPe 281 TRIGger[:SEQuence[1]]:COUNt 283 TRIGger[:SEQuence[1]]:DELay:AUTO 285 TRIGger[:SEQuence[1]]:IMMediate 287 TRIGger[:SEQuence[1]]:SOURce BUS|EXTernal|HOLD|IMMediate 288 12 UNIT Subsystem UNIT Subsystem 292 UNIT[1]:POWer 293 13 IEEE 488.2 Command Reference SCPI Compliance Information 296 *CLS 297 *ESE 298 *ESR? 300 *IDN? 301 *OPC 302 *OPT? 303 *RCL 304 *RST 305 *SAV 306 *SRE 307 *STB? 309 *TRG 311 *TST? 312 *WAI 313 USBTMC/USB488 Universal Commands 314

Programming Guide Agilent Technologies 1 Power Sensor Remote Operation Introduction 3 Configuring the Remote Interface 4 • Interface Selection 4 • USB Configuration 4 Zeroing and Calibrating the U2000 Series USB Power Sensors 5 • Zeroing 5 • Calibration 5 Making Measurement 7 • Using MEASure? 8 • Using the CONFigure Command 10 • Using the Lower Level Commands 15 Using Frequency Dependent Offset Tables 17 • Overview 17 • Editing Frequency Dependent Offset Tables 19 • Selecting a Frequency Dependent Offset Table 22 • Enabling a Frequency Dependent Offset Table 22 • Making the Measurement 22 Setting the Range and Averaging 24 • Averaging 24 • Auto Averaging Mode 24 • Filter Length 26 Range 26

2 U2000 Series Programming Guide Setting Offsets 27 • Channel Offsets 27 Setting Measurement Limits 28 • Setting Limits 28 • Checking for Limit Failures 29 Getting the Best Speed Performance 31 • Measurement Rate 31 • Trigger Mode 31 • Output Format 33 • Units 33 • Command Used 33 • Fast Mode 34 How Measurements are Calculated 35 Status Reporting 36 • The General Status Register Model 36 • How to Use Register 39 • The Condition Polling Method 39 • Status Registers 39 • Device Status Register 47 • Using the Operation Complete Commands 49 Saving and Recalling Power Sensor Configurations 50 • How to Save and Recall a Configuration 50 Using Device Clear to Halt Measurements 51 An Introduction to the SCPI Language 52 • Mnemonic Forms 52 • Using a Colon (:) 52 • Using a Semicolon (;) 53 • Using a Comma (,) 53 • Using Whitespace 53 • Using “?” Commands 53 • Using “*” Commands 54 • Syntax Conventions 54 • Syntax Diagram Conventions 54 • SCPI Data Types 55 • Input Message Terminators 61 SCPI Compliance Information 62 Summary of Commands 63 This chapter describes the parameters that configure the power sensor and helps you determine settings to optimize performance.

1 U2000 Series Programming Guide 3 Introduction This chapter describes the parameters which configure the power sensor and help you determine settings to optimize performance. It contains the following sections: • “Configuring the Remote Interface” on page 4. • “Zeroing and Calibrating the U2000 Series USB Power Sensors” on page 5. • “Making Measurement” on page 7. • “Using Frequency Dependent Offset Tables” on page 17. • “Setting the Range and Averaging” on page 24. • “Setting Offsets” on page 27. • “Setting Measurement Limits” on page 28. • “Getting the Best Speed Performance” on page 31. • “How Measurements are Calculated” on page 35. • “Status Reporting” on page 36. • “Saving and Recalling Power Sensor Configurations” on page 50. • “Using Device Clear to Halt Measurements” on page 51. • “An Introduction to the SCPI Language” on page 52. • “SCPI Compliance Information” on page 62. • “Summary of Commands” on page 63.

4 U2000 Series Programming Guide Configuring the Remote Interface This section briefly describes how to configure the USB interface. Interface Selection You can choose to control the power sensor using the USB interface. USB Configuration The USB interface requires no front panel or remote configuration. The USB address cannot be changed - it is set at the factory and is unique for each power sensor. NOTE For more information on configuring the USB remote interface connectivity, refer to the Agilent Technologies USB/LAN/GPIB Interfaces Connectivity Guide. If you have installed the IO Libraries Suite, you can access the Connectivity Guide via the Agilent IO Libraries Control icon. Alternatively, you can access the Connectivity Guide via the Web at www.agilent.com/find/connectivity. NOTE Before connecting the USB cable, make sure that I/O software is installed on your computer. NOTE For more information about Agilent IO Libraries software refer to the Connectivity Guide. If you have installed other I/O Software, refer to documentation that accompanies the software.

1 U2000 Series Programming Guide 5 Zeroing and Calibrating the U2000 Series USB Power Sensors The U2000 Series USB power sensors do not need manual calibration and zero routines performed. These are performed without removing the power sensor from the source, which is known as internal zeroing. With internal zeroing of U2000 Series USB power sensors, there is no need to disconnect the sensor or power- off the device- under- test (DUT). The U2000 Series does not require 50 MHz reference signal calibration, thus allowing factory calibration for ensuring measurement accuracy. However, users are recommended to perform external zeroing for input signals below –30 dBm for best accuracy. Zeroing Zeroing adjusts the power sensor for a zero power reading. The command CALibration[1]:ZERO:AUTO [ONCE|ON|OFF|0|1] causes the power sensor to perform its zeroing routine when enabled. This adjusts the power sensor for a zero power reading. 1|ON can only be used for internal zeroing. When 1|ON is enabled the zero is maintained by a combination of zero on- the- fly for measurements and temperature compensation. Zeroing of the power sensor happens automatically: • When a 5 oC change in temperature occurs • When you change the power sensor • Every 24 hours To perform external zeroing, the command CALibration[1]:ZERO:TYPE EXTernal is used, following by CALibration[1]:ZERO:AUTO ONCE to start the zeroing process. Calibration There is no calibration needed in U2000 Series USB power sensors. The

6 U2000 Series Programming Guide command CALibration[1]:AUTO ONCE shows the code compatibility with CALibration[1]:ZERO:AUTO ONCE. Users are not required to modify their source code which is used in other power meters or sensors as CALibration[1]:AUTO ONCE supports backward compatibility. Calibration Sequence This feature allows you to perform a complete calibration sequence with a single query. The query is: CALibration[1][:ALL]? The complete calibration sequence consists of: • Zeroing and calibrating the power sensor (CALibration[1]:ZERO:AUTO ONCE or CALibration[1]:AUTO ONCE) The query enters a number into the output buffer when the sequence is complete. If the result is 0 the sequence was successful. If the result is 1 the sequence failed. Refer to “CALibration[1][:ALL]?” on page 110 for further information. NOTE The CALibration[1][:ALL] command is identical to the CALibration[1][:ALL]? query except that no number is returned to indicate the outcome of the sequence. You can examine the Questionable Status Register or the error queue to discover if the sequence has passed or failed. Refer to “Status Reporting” on page 36 for further information.

1 U2000 Series Programming Guide 7 Making Measurement The MEASure? and CONFigure commands provide a straight- forward method to program the power sensor for measurements. You can select the measurement’s expected power level and resolution all in one command. The power sensor automatically presets other measurement parameters to default values as shown in Table 1- 1 below. Table 1-1 MEASure? and CONFigure Preset States An alternative method to program the power sensor is to use the lower level commands. The advantage of using the lower level commands over the CONFigure command is that they give you more precise control of the power sensor. As shown in Table 1- 1, the CONFigure command presets various states in the power sensor. It may be likely that you do not want to preset these states. Refer to “Using the Lower Level Commands” on page 15 for further information. Command MEASure? and CONFigure Setting Trigger source (TRIGger:SOURce) Immediate Filter ([SENSe[1]]:AVERage:COUNt:AU TO) On Filter state([SENSe[1]]:AVERage:STATe ) On Trigger cycle (INITiate:CONTinuous) Off TriggerDelay (TRIGger:DELay:AUTO) On

8 U2000 Series Programming Guide Using MEASure? The simplest way to program the power sensor for measurements is by using the MEASure? query. However, this command does not offer much flexibility. When you execute the command, the power sensor selects the best settings for the requested configuration and immediately performs the measurement. You cannot change any settings (other than the expected power value and resolution) before the measurement is taken. This means you cannot fine tune the measurement, for example, you cannot change the filter length. To make more flexible and accurate measurements use the CONFIGure command. The measurement results are sent to the output buffer. MEASure? is a compound command which is equivalent to an ABORT, followed by a CONFigure, followed by a READ?. MEASure? Examples The following commands show a few examples of how to use the MEASure? query to make a measurement. It is advisable to read through these examples in order as they become increasingly more detailed. These examples configure the power sensor for a measurement (as described in each individual example), automatically place the power sensor in the “wait- for- trigger” state, internally trigger the power sensor to take one reading, and then sends the reading to the output buffer. These examples give an overview of the MEASure? query. For further information on the MEASure? commands refer to the section “MEASurement Commands” on page 66. Example 1 - The Simplest Method The following commands show the simplest method of making measurements. Using MEAS1? results in the current window measurement. Example 2 - Specifying the Source List Parameter The MEASure command has three optional parameters, an expected power MEAS1? current window

1 U2000 Series Programming Guide 9 value, a resolution and a source list. These parameters must be entered in the specified order. If parameters are omitted, they default from the right. The parameter DEFault is used as a place holder. .The expected power and resolution parameters are defaulted, leaving them at their current settings. The measurement is carried out on the current window. Example 3 - Specifying the Expected Power Parameter The previous example details the three optional parameters which can be used with the MEASure? command. The first optional parameter is used to enter an expected power value. The value entered determines which of the power sensor’s two ranges is used for the measurement. If the current setting of the power sensor’s range is no longer valid for the new measurement, specifying the expected power value decreases the time taken to obtain a result. The following example uses the expected value parameter to specify a value of –50 dBm. This selects the power sensor’s lower range (refer to “Range” on page 26 for details of the range breaks). The resolution parameter is defaulted, leaving it at its current setting. Example 4 - Specifying the Resolution Parameter The previous examples detailed the use of the expected value and source list parameters. The resolution parameter is used to set the resolution of the current window. This parameter does not affect the resolution of the data, however it does affect the auto averaging setting (refer to Figure 1- 3). The following example uses the resolution parameter to specify a resolution setting of 3. This setting represents 3 significant digits if the measurement suffix is W or %, and 0.01 dB if the suffix is dB or dBm. Refer to Chapter 2, “MEASurement Commands”on page 65, for further details on the resolution parameter. The expected power and source list parameters are defaulted in the example. The expected power value remains unchanged at its current MEAS1? DEF,DEF,(@1) current window MEAS1? -50,DEF,(@1) current window specifies expected power value

10 U2000 Series Programming Guide setting. Note that as the source list parameter is the last specified parameter you do not have to specify DEF. The measurement is carried out on the current window. Using the CONFigure Command When you execute this command, the power sensor presets the optimum settings for the requested configuration (like the MEASure? query). However, the measurement is not automatically started and you can change measurement parameters before making measurements. This allows you to change the power sensor’s configuration from the preset conditions. The power sensor offers a variety of low- level commands in the SENSe, CALCulate, and TRIGger subsystems. For example, if you want to change the averaging use the [SENSe[1]]:AVERage:COUNt command. Use the INITiate or READ? query to initiate the measurement. Using READ? CONFigure does not take the measurement. One method of obtaining a result is to use the READ? query. The READ? query takes the measurement using the parameters set by the CONFigure command then sends the reading to the output buffer. Using the READ? query obtains new data. Using INITiate and FETCh? CONFigure does not take the measurement. One method of obtaining the result is to use the INITiate and FETCh? commands. The INITiate command causes the measurement to be taken. The FETCh? query retrieves a reading when the measurement is complete, and sends the reading to the output buffer. FETCh? can be used to display the measurement results in a number of different formats without taking fresh data for each measurement. CONFigure Examples The following program segments show how to use the commands READ?, MEAS1? DEF,3 current window specifies resolution setting

1 U2000 Series Programming Guide 11 INITiate and FETCh? and CONFigure to make measurements. It is advisable to read through these examples in order as they become increasingly more detailed. These examples give an overview of the CONFigure command. For further information on the CONFigure commands refer to Chapter 2, “MEASurement Commands”. Example 1 - The Simplest Method The following program segments show the simplest method of querying the current window’s measurement results respectively. Using READ? Using INITiate and FETCh? Example 2 - Specifying the Source List Parameter The CONFigure and READ? commands have three optional parameters, an expected power value, a resolution and a source list. These parameters must be entered in the specified order. If parameters are omitted, they default from the right. The parameter DEFault is used as a place holder. The following examples use the source list parameter to specify the measurement. The expected power and resolution parameters are defaulted, leaving them at their current settings. The measurement is carried out on the current window. Although the READ? and FETCh? queries have three optional parameters it is not necessary to define them as shown in these examples. If they are defined they must be identical to those defined in the CONFigure command otherwise *RST Reset instrument CONF1 Configure current window - defaults to a measurement READ1? Take current window measurement *RST Reset instrument CONF1 Configure current window - defaults to a measurement INIT1 Causes a measurement FETC1? Retrieves the current window’s measurement

12 U2000 Series Programming Guide an error occurs. Using READ? Using INITiate and FETCh? Example 3 - Specifying the Expected Power Parameter The previous example details the three optional parameters which can be used with the CONFigure and READ? commands. The first optional parameter is used to enter an expected power value. The value entered determines which of the power sensor’s two ranges is used for the measurement. If the current setting of the power sensor’s range is no longer valid for the new measurement, specifying the expected power value decreases the time taken to obtain a result. The following example uses the expected value parameter to specify a value of –50 dBm. This selects the power sensor’s lower range (refer to “Range” on page 26 for details of the range breaks). The resolution parameter is defaulted, leaving it at its current setting. ABOR1 Aborts measurement CONF1 DEF,DEF,(@1) Configures the current window to make a measurement using the current expected power and resolution settings READ1? Takes the current window’s measurement ABOR1 Aborts measurement CONF1 DEF,DEF,(@1) Configures the current window to make a measurement using the current expected power and resolution settings INIT1 Causes a measurement FETC1? DEF,DEF,(@1) Retrieves the current window’s measurement

1 U2000 Series Programming Guide 13 Using READ? Some fine tuning of measurements can be performed using the CONFigure and READ? commands. For example, in the above program segment some fine tuning can be performed by setting the filter length to 1024 and the trigger delay off. 1 ABOR1 2 CONF1 -50,DEF,(@1) 3 SENS1:AVER:COUN 1024 4 TRIG1:DEL:AUTO OFF 5 READ1? Using INITiate and FETCh? Some fine tuning of measurements can be carried out using the CONFigure command and INITiate and FETCh? commands. For example, in the above program segment some fine tuning can be carried out by setting the filter length to 1024 and the trigger delay off. 1 ABOR1 2 CONF1 -50,DEF,(@1) 3 SENS1:AVER:COUN 1024 ABOR1 Aborts current measurement CONF1 -50,DEF,(@2) Configures the current measurement to use an expected power of –50 dBm and the current resolution setting READ1? Takes the current measurement ABOR1 Aborts current measurement CONF1 -50,DEF,(@1) Configures the current measurement to use an expected power of –50 dBm and the current resolution setting INIT1 Causes a measurement FETC1? -50,DEF,(@1) Retrieves the current measurement

14 U2000 Series Programming Guide 4 TRIG1:DEL:AUTO OFF 5 INIT1 6 FETC1? -50,DEF,(@1) Example 4 - Specifying the Resolution Parameter The previous examples detailed the use of the expected value and source list parameters. The resolution parameter is used to set the resolution of the measurement. This parameter does not affect the resolution of the data, however it does affect the auto averaging setting (refer to Figure 1- 3 on page 25). The following example uses the resolution parameter to specify a resolution setting of 3. This setting represents 3 significant digits if the measurement suffix is W or %, and 0.01 dB if the suffix is dB or dBm (for further details on the resolution parameter refer to the commands in Chapter 2, “MEASurement Commands”). Also, in this example the expected power and source list parameters are defaulted. The expected power value is left unchanged at its current setting. Note that as the source list parameter is the last specified parameter you do not have to specify DEF. Using READ? Some fine tuning of the above program segment can be carried out for example, by setting the trigger delay off. The following program segment assumes that it is being measured in the measurement. 1 ABOR1 2 CONF1 DEF,3 3 TRIG1:DEL:AUTO OFF 4 READ1? ABOR1 Aborts current measurement CONF1 DEF,3 Configures the current measurement to use the current setting of the expected power and source list and a resolution setting of 3 READ1? Takes the current measurement. This is a measurement depending on current window setup.

1 U2000 Series Programming Guide 15 Using INITiate and FETCh? The following program segment assumes that it is being measured on the current window. Some fine tuning of the above program segment can be carried out for example, by setting the trigger delay off. 1 ABOR1 2 CONF1 DEF,3 3 TRIG1:DEL:AUTO OFF 4 INIT1:IMM 5 FETC1? DEF,3 Using the Lower Level Commands An alternative method of making measurements is to use the lower level commands to set up the expected range and resolution. This can be done using the following commands: [SENSe[1]]:POWer:AC:RANGe The measurement type can be set using the following commands in the CALCulate subsystem: CALCulate[1]:MATH[:EXPRession] The advantage of using the lower level commands over the CONFigure command is that they give you more precise control of the power sensor. As shown in Table 1- 1 the CONFigure command presets various states in the ABOR1 Aborts current measurement CONF1 DEF,3 Configures the current measurement to use the current setting of the expected power and source list and a resolution setting of 3 INIT1 Causes a measurement FETC1? DEF,3 Retrieves the current measurement

16 U2000 Series Programming Guide power sensor. It may be likely that you do not want to preset these states. Example The following example sets the expected power value to –50 dBm and the resolution setting to 3 using the lower level commands. ABOR1 Aborts current measurement CALC1:MATH:EXPR "(SENS1)" Displays current measurement SENS1:POW:AC:RANG -50 Sets lower range INIT1 Causes a measurement FETC1? Retrieves the current measurement

1 U2000 Series Programming Guide 17 Using Frequency Dependent Offset Tables This section describes how to use frequency dependent offset tables. These tables give you the ability to compensate for frequency effects in your test setup. Overview If the [SENSe[1]]:CORRection:CSET2:STATe command is OFF, the frequency dependent offset tables are not used. When [SENSe[1]]:CORRection:CSET2:STATe is ON, the frequency dependent offset tables are used, providing you with a quick and convenient method of compensating for your external test setup over a range of frequencies. Note that when selected, frequency dependent offset correction is IN ADDITION to any correction applied for sensor frequency response. The power sensor is capable of storing 10 frequency dependent offset tables of 80 frequency points each. To use frequency dependent offset tables you: 1 Edit a frequency dependent offset table if necessary. 2 Select the frequency dependent offset table. 3 Enable the frequency dependent offset table. 4 Zero and calibrate the power sensor. 5 Specify the frequency of the signal you want to measure. The required offset is automatically set by the power sensor from the frequency dependent offset table. 6 Make the measurement. Figure 1- 1 illustrates how frequency dependent offset tables operate.

18 U2000 Series Programming Guide Figure 1-1 Frequency Dependent Offset Tables TABLE N FREQ FREQ 1 . . . . . . . . . . . FREQ 2 80 OFFSET OFFSET 1 . . . . . . . . . . . 80 TABLE 1 FREQ FREQ 1 . . . . . . . . . . . FREQ 2 80 OFFSET OFFSET 1 . . . . . . . . . . . 2 80 TABLE 10 FREQ FREQ 1 . . . . . . . . . . . FREQ 2 80 OFFSET OFFSET 1 . . . . . . . . . . . OFFSET 2 80 OFFSET = Frequency Dependent Offset FREQ FREQ 1 . . . . . . . . . . . FREQ 2 80 OFFSET OFFSET 1 . . . . . . . . . . . OFFSET 2 80 Frequency of the signal you want to measure TABLE SELECTED OFFSET 2 OFFSET Frequency dependent offset used to make Measurement. Calculated by the Power Sensor using linear interpolation.

1 U2000 Series Programming Guide 19 Editing Frequency Dependent Offset Tables It is not possible to create any additional frequency dependent offset tables. However, the 10 existing tables can be edited using the MEMory subsystem. To do this: 1 Select one of the existing tables using: MEMory:TABle:SELect For information on naming frequency dependent offset tables see “Naming Frequency Dependent Offset Tables” on page 21. For information on the current names which you can select refer to “Listing the Frequency Dependent Offset Table Names” on page 20. 2 Enter the frequency data using: MEMory:TABle:FREQuency {,} 3 Enter the offset factors as shown in the table below using: MEMory:TABle:GAIN {,} 4 If required, rename the frequency dependent offset table using: MEMory:TABLe:MOVE ,. The first parameter identifies the existing table name, and the second identifies the new table name. Frequency Offset Frequency 1 Offset 1 Frequency 2 Offset 2 " " Frequency n Offset n

20 U2000 Series Programming Guide Listing the Frequency Dependent Offset Table Names To list the frequency dependent offset tables currently stored in the power sensor, use the following command: MEMory:CATalog:TABLe? The power sensor returns the data in the form of two numeric parameters and a string list representing all stored tables. • ,{,} The first numeric parameter indicates the amount of memory, in bytes, used for storage of tables. The second parameter indicates the memory, in bytes, available for tables. Each string parameter returned indicates the name, type and size of a stored frequency dependent offset table: • ,, The , and are all character data. The is always TABL. The is displayed in bytes. For example, a sample of the response may look like: 560,8020,“Offset_1,TABL,220”,”Offset_2,TABL,340” .... NOTE The legal frequency suffix multipliers are any of the IEEE suffix multipliers, for example, KHZ, MHZ, and GHZ. If no units are specified the power sensor assumes the data is Hz. PCT is the only legal unit for offset factors and can be omitted. The frequency and offset data must be within range. Refer to the individual commands in Chapter 4 for their specified ranges. Any offset values entered into the table should exclude the effect of the sensor. Characterization of the test setup independently of the sensor allows the same table to be used with any sensor. Ensure that the frequency points you use cover the frequency range of the signals you want to measure. If you measure a signal with a frequency outside the frequency range defined in the frequency dependent offset table, then the power sensor uses the highest or lowest frequency point in the table to calculate the offset. To make subsequent editing of a frequency dependent offset table simpler, it is recommended that you retain a copy of your data in a program.

1 U2000 Series Programming Guide 21 Naming Frequency Dependent Offset Tables To rename a frequency dependent offset table use: MEMory:TABLe:MOVE , The first parameter identifies the existing table name, and the second identifies the new table name. The following rules apply to frequency dependent offset table names: 1 Table names use a maximum of 12 characters. 2 All characters must be upper or lower case alphabetic characters, or numeric (0- 9), or an underscore (_). No spaces are allowed in the name. Reviewing Table Data To review the data stored in a frequency dependent offset table, use the following commands: MEMory:TABLe:SELect "Offset1" Select the frequency dependent offset table named “Offset1”. MEMory:TABLe:SELect? Query command which returns the name of the currently selected table. MEMory:TABLe:FREQuency:POINTs? Query command which returns the number of stored frequency points. MEMory:TABLe:FREQuency? Query command which returns the frequencies stored in the frequency dependent offset table (in Hz). MEMory:TABLe:GAIN[:MAGNitude]:POINTs? Query command which returns the number of offset factor points stored in the frequency dependent offset table. MEMory:TABLe:GAIN[:MAGNitude]? Query command which returns the offset factors stored in the frequency dependent offset table. Modifying Data If you need to modify the frequency and offset factor data stored in a frequency dependent offset table you need to resend the complete data lists. If you have retained the original data in a program, edit the program and resend the data.

22 U2000 Series Programming Guide Selecting a Frequency Dependent Offset Table After you have created the frequency dependent offset table, you can select it using the following command: [SENSe[1]]:CORRection:CSET2[:SELect] To find out which frequency dependent offset table is currently selected, use the query: [SENSe[1]]:CORRection:CSET2[:SELect]? Enabling a Frequency Dependent Offset Table To enable the frequency dependent offset table, use the following command: [SENSe[1]]:CORRection:CSET2:STATe ON If you set [SENSe[1]]:CORRection:CSET2:STATe to ON and no frequency dependent offset table is selected error –221, “Settings conflict” occurs. Making the Measurement To make the power measurement, set the power sensor for the frequency of the signal you want to measure. The power sensor automatically sets the offset factor. Use either the INITiate, FETCh? or the READ? query to initiate the measurement as shown in the following program segments: INITiate Example ABORt1 CONFigure1:POWer:AC DEF,1,(@1) SENS1:CORR:CSET2:SEL "Offset1" SENS1:CORR:CSET2:STAT ON SENS1:FREQuency 500KHZ INITiate1:IMMediate FETCh1?

1 U2000 Series Programming Guide 23 READ? Example ABORt1 CONFigure1:POWer:AC DEF,2,(@1) SENS1:CORR:CSET2:SEL "Offset1" SENS1:CORR:CSET2:STAT ON SENS1:FREQuency 500KHZ READ1? NOTE If the measurement frequency does not correspond directly to a frequency in the frequency dependent offset table, the power sensor calculates the offset using linear interpolation. If you enter a frequency outside the frequency range defined in the frequency dependent offset table, then the power sensor uses the highest or lowest frequency point in the table to set the offset. To find out the value of the offset being used by the power sensor to make a measurement, use the query command: [SENSe[1]]:CORRection:GAIN4|FDOFfset[:INPut][MAGNITUDE]? The response may be an interpolated value.

24 U2000 Series Programming Guide Setting the Range and Averaging This section provides an overview of setting the range, resolution and averaging. For more detailed information about these features refer to the individual commands in Chapter 7, “SENSe Subsystem”. Averaging The power sensor has a digital filter to average power readings. The number of readings averaged can range from 1 to 2048. This filter is used to reduce noise, obtain the desired resolution and to reduce the jitter in the measurement results. However, the time to take the measurement is increased. You can select the filter length or you can set the power sensor to auto filter mode. To enable and disable averaging use the following command: [SENSe[1]]:AVERage[:STATe] Auto Averaging Mode To enable and disable auto filter mode, use the following command: [SENSe[1]]:AVERage:COUNt:AUTO When the auto filter mode is enabled, the power sensor automatically sets the number of readings averaged together to satisfy the filtering requirements for most power measurements. The number of readings averaged together depends on the resolution and the power level currently being measured. Figure 1- 3 illustrates part of the power sensor dynamic range hysteresis.

1 U2000 Series Programming Guide 25 Figure 1-2 Typical averaged readings on U2000 Series USB power sensors Figure 1-3 Averaging Range Hysteresis Minimum Sensor Power Minimum Sensor Power + 10 dB Range Hysteresis 10.5 dB 9.5 dB

26 U2000 Series Programming Guide Filter Length You specify the filter length using the following command: [SENSe[1]]:AVERage:COUNt The range of values for the filter length is 1 to 2048. Specifying this command disables automatic filter length selection. Increasing the value of the filter length reduces measurement noise. However, the time to take the measurement is increased. Range With an U2000 Series USB Power Sensor the range can be set either automatically or manually. Use autoranging when you are not sure of the power level you will be measuring. Setting the Range To set the range manually use the following command: [SENSe[1]]:POWer:AC:RANGe If the is set to: • 0, the sensor’s lower range is selected. • 1, the sensor’s upper range is selected. For detailed on the range limits of U2000 Series USB power sensors, refer to the U2000 Series USB Power Sensors Operating and Service Guide. For further information on this command refer to page 198. To enable autoranging use the following command: [SENSe[1]]:POWer:AC:RANGe:AUTO ON Use autoranging when you are not sure of the power level you will be measuring.

1 U2000 Series Programming Guide 27 Setting Offsets Channel Offsets The power sensor can be configured to compensate for signal loss or gain in your test setup (for example, to compensate for the loss of a 10 dB attenuator). You use the SENSe command subsystem to configure the power sensor. Gain and loss correction are a coupled system. If you enter an offset value the state is automatically enabled. However it can be enabled and disabled using either the [SENSe[1]]:CORRection:GAIN2:STATe. NOTE To enter a LOSS value, you can enter a negative value in the command [SENSe[1]]:CORRection:GAIN2[:INPut][:MAGNitude].

28 U2000 Series Programming Guide Setting Measurement Limits You can configure the power sensor to detect when a measurement is outside of a predefined upper and/or lower limit value. Limits are measurement display line based and can be applied to power measurement. Setting Limits The power sensor can be configured to verify the power being measured against an upper and/or lower limit value. The range of values that can be set for lower and upper limits is –150.00 dBm to +230.00 dBm. The default upper limit is +90.00 dBm and the default lower limit is –90.00 dBm. Figure 1-4 Limits Checking Results +4 dBm +10 dBm Amplitude Frequency o o o o o o o Fail Fail

1 U2000 Series Programming Guide 29 Setting Limits (Check Header - same as previous) The power sensor can be configured to verify the current measurement in any measurement line against predefined upper and/or lower limit values. The range of values that can be set for the upper and lower limits and the default values depends on the measurement units in the currently measurement line - see Table 1- 2. Table 1-2 Range of Values for Measurement Limits Checking for Limit Failures There is a way to check for limit failures: • Use the CALCulate[1]:LIMit:FAIL? and CALCulate[1]:LIMit:FCOunt? commands for measurement limits Using CALCulate Using CALCulate to check the measurement limit failures in Figure 1- 4 would return the following results: Window Units Default Maximum Minimum Maximum Minimum dB +200 dB –180 dB 60 dB –120 dB dBm +230 dBm –150 dBm 90 dBm –90 dBm % 999.9 X% 100.0 a% 100.0 M% 100.0 p% W 100.000 XW 1.000 aW 1.000 MW 1.000 pW CALCulate[1]:LIMit:FAIL? Returns 1 if there has been 1 or more limit failures or 0 if there have been no limit failures. In this case 1 is returned. CALCulate[1]:LIMit:FCOunt? Returns the total number of limit failures, in this case 2.

30 U2000 Series Programming Guide NOTE If TRIGger:DELay:AUTO is set to ON, then the number of failures returned by CALCulate[1]:LIMit:FCOunt? is affected by the current filter settings.

1 U2000 Series Programming Guide 31 Getting the Best Speed Performance This section discusses the factors that influence the speed of operation (number of readings/sec) of U2000 Series USB power sensors. The following factors are those which have the greatest effect upon measurement speed (in no particular order): • The selected measurement rate, i.e. NORMal, DOUBle, FAST. • The trigger mode (for example, free run, trigger with delay etc.). • The output format: ASCii or REAL. • The units used for the measurement. • The command used to take a measurement. In addition, in FAST mode there are other influences which are described in “Fast Mode” on page 34. The following paragraphs give a brief description of the above factors and how they are controlled from SCPI. Measurement Rate There are three possible speed settings NORMal, DOUBle and FAST. These are set using the [SENSe[1]]:MRATe command. In NORMal and DOUBle modes, full instrument functionality is available. In FAST mode averaging, limits are disabled. Refer to “Specifications” in the U2000 Series USB Power Sensors Operating and Service Guide to see the influence of these speed settings on the accuracy and noise performance of the power sensor. Trigger Mode The power sensor has a very flexible triggering system. For simplicity, it can be described as having three modes:

32 U2000 Series Programming Guide • Free Run: When a channel is in Free Run, it continuously takes measurements. A measurement is in free run when INITiate:CONTinuous is set to ON and TRIGger:SOURce is set to IMMediate. • Triggered Free Run: When a channel is in Triggered Free Run Continuous Trigger, it takes a new measurement each time a trigger event is detected. A channel is in Triggered Free Run Continuous Trigger when INITiate:CONTinuous is set to ON and TRIGger:SOURce is not set to IMMediate. • Single Shot: When a channel is in Single Shot, it takes a new measurement when a trigger event is detected and then returns to the idle state. A channel is in Single Shot when INITiate:CONTinuous is set to OFF. Note that a measurement can take several EXT triggers depending on the filter settings. Refer to “TRIGger[1]:DELay:AUTO ” on page 275 for further information. Trigger with Delay This can be achieved using the same sequences above (apart from the second) with TRIG:DEL:AUTO set to ON. Also, the MEAS? command operates in trigger with delay mode. In trigger with delay mode, a measurement is not completed until the power sensor filter is full. In this way, the reading returned is guaranteed to be settled. In all other modes, the result returned is simply the current result from the filter and may or may not be settled. This depends on the current length of the filter and the number of readings that have been taken since a change in power level. With trigger with delay enabled, the measurement speed can be calculated roughly using the following equation: readings/sec = speed (as set by [SENSe[1]]:MRATe)/ filter length NOTE A trigger event can be any of the following: • The input signal meeting the trigger level criteria. • Auto-level triggering being used. • A TRIGger[1][:IMMediate] or *TRG command being sent. • An external TTL level trigger being detected.

1 U2000 Series Programming Guide 33 For example, with a filter length of 4 and SENS[1]:MRATe set to NORMal, approximately 5 readings/sec is calculated by the power sensor. Output Format The power sensor has two output formats for measurement results: ASCii and REAL. These formats are selected using the FORMat command. When FORMat is set to REAL, the returned result is in IEEE 754 floating- point format (note that the byte order can be changed using FORMat:BORDer) plus as an end sentinel of the block. The REAL format is likely to be required only for FAST mode as it reduces the amount of bus traffic. Units The power sensor can output results in either linear or log units. The internal units are linear, therefore optimal performance is achieved when the results output are also in linear units (since the overhead of performing a log function is removed). Command Used In Free Run mode, FETCh? must be used to return a result. In other trigger modes, there are a number of commands which can be used, for example, MEASure?, READ?, FETCh? Note that the MEAS? and READ? commands are compound commands—they perform a combination of other lower level commands. Typically, the best speed performance is achieved using the low level commands directly. Trigger Count To get the fastest measurement speed TRIG:COUNT must be set to return multiple measurements for each FETCh command. For average only measurements a count of 4 is required, however, 10 is recommended.

34 U2000 Series Programming Guide Fast Mode In the highest speed setting, the limiting factor tends to be the speed of the controller being used to retrieve results from the power sensor, and to a certain extent, the volume of remote traffic. The latter can be reduced using the FORMat REAL command to return results in binary format. The former is a combination of two factors: • the hardware platform being used • the programming environment being used

1 U2000 Series Programming Guide 35 How Measurements are Calculated Figure 1- 5 details how measurements are calculated. It shows the order in which the various power sensor functions are implemented in the measurement calculation. Figure 1-5 How Measurement are Calculated The MEASure commands in this figure can be replaced with the FETCh? and READ? commands. TRIGger UNIT1 Conversion :POW CALCulate1 Maths Limits :MATH :LIM Switch :FEED SENSe1 Sensor Filter Freq. Corr. Offset :SPEed :POW:AC:RANG :POW:AC:RANG:AUTO :DET:FUNC :AVER[1] :FREQ :CORR:CFAC :CORR:CSET :CORR:GAIN2 Data Selection FORMat MEAS? READ? FETC? CONF Switch

36 U2000 Series Programming Guide Status Reporting Status reporting is used to monitor the power sensor to determine when events have occurred. Status reporting is accomplished by configuring and reading status registers. The power sensor has the following main registers: • Status Register • Standard Event Register • Operation Status Register • Questionable Status Register • Device Status Register There are other registers that exist “behind” the main registers, and are described later in this chapter. Status and Standard Event registers are read using the IEEE- 488.2 common commands. Operation and Questionable Status registers are read using the SCPI STATus command subsystem. The General Status Register Model The generalized status register model shown in Figure 1- 6 is the building block of the SCPI status system. This model consists of a condition register, a transition filter, an event register and an enable register. A set of these registers is called a status group.

1 U2000 Series Programming Guide 37 Figure 1-6 Generalized Status Register Model When a status group is implemented in an instrument, it always contains all of the component registers. However, there is not always a corresponding command to read or write to every register. Condition Register The condition register continuously monitors the hardware and firmware status of the power sensor. There is no latching or buffering for this register, it is updated in real time. Condition registers are read- only. Transition Filter The transition filter specifies which types of bit state changes in the condition registers and set corresponding bits in the event register. Transition filter bits may be set for positive transitions (PTR), negative transitions (NTR), or both. Transition filters are read- write. They are unaffected by *CLS or queries. After STATus:PRESet the NTR register is set to 0 and all bits of the PTR are set to 1. Event Register The event register latches transition events from the condition register as specified by the transition filter. Bits in the event register are latched and on setting they remain set until cleared by a query or a *CLS. Also on setting, an event bit is no longer affected by condition changes. It remains set until the event register is cleared; either when you read the register or when you send the *CLS (clear status) command. Event registers are read- only. 0 1 2 Bit 0 Bit 1 Bit 2 Bit 3 Condition Register Transition Filter Event Register Enable Register Logical OR Summary Bit

38 U2000 Series Programming Guide Enable Register The enable register specifies the bits in the event register that can generate a summary bit. The instrument logically ANDs corresponding bits in the event and enable registers and ORs all the resulting bits to obtain a summary bit. Enable registers are read- write. Querying an enable register does not affect it. An Example Sequence Figure 1- 7 illustrates the response of a single bit position in a typical status group for various settings. The changing state of the condition in question is shown at the bottom of the figure. A small binary table shows the state of the chosen bit in each status register at the selected times T1 to T5. Figure 1-7 Typical Status Register Bit Changes 0 0 0 1 1 1 0 0 1 1 0 1 0 0 0 0 0 0 0 1 1 1 0 1 1 0 1 0 0 0 1 1 0 0 1 0 1 0 0 0 1 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 A B C D Condition PTR NTR Enable Condition Event Summary Bit Condition Event Summary Bit Condition Event Summary Bit Condition Event Summary Bit Condition Event Summary Bit 1 0 T1 T2 T3 T4 T5 0 0 0 0 0 0 * * * * marks when event register is read

1 U2000 Series Programming Guide 39 How to Use Register There is a method to access the information in status groups: • the polling method Use the polling method when: • your language/development environment does not support SRQ interrupts. • you want to write a simple, single purpose program and do not want to add the complexity of setting an SRQ handler. The Condition Polling Method In this polling method, the power sensor has a passive role. It only informs the controller that conditions have changed when the controller asks. When you monitor a condition with the polling method, you must: 1 Determine which register contains the bit that monitors the condition. 2 Send the unique query that reads that register. 3 Examine the bit to see if the condition has changed. The polling method works well if you do not need to know about the changes the moment they occur. Detecting an immediate change in a condition using the polling method requires your program to continuously read the registers at very short intervals. This is not particularly efficient and there is a possibility that an event may be missed. Status Registers The Status System in the power sensor is shown in Figure 1- 8. The Operation Status and Questionable Status groups are 16 bits wide, while the Status Byte and Standard Event groups are 8 bits wide. In all 16- bit groups, the most significant bit (bit 15) is not used and is always set to 0.

40 U2000 Series Programming Guide Figure 1-8 Status System Questionable Status Logical OR Condition Event Enable Operation Status Logical OR Condition Event Enable Standard Event Logical OR Event Enable *ESR *ESE Status Byte Logical OR *STB? *SRE MAV 0 1 2 QUE ESB RQS/MSS OPR MAV 0 1 2 QUE ESB X OPR Output Queue Device Status Logical OR Condition Event Enable Error/Event Queue

1 U2000 Series Programming Guide 41 The Status Byte Summary Register The status byte summary register reports conditions from other status registers. Query data waiting in the power sensor’s output buffer is immediately reported through the “message available” bit (bit 4). Clearing an event register clears the corresponding bits in the status byte summary register. Reading all messages in the output buffer, including any pending queries, clears the message available bit. Table 1-3 Bit Definitions - Status Byte Register Particular bits in the status byte register are cleared when: • The standard event, Questionable status, operation status and device status are queried. • The error/event queue becomes empty. • The output queue becomes empty. Bit Number Decimal Weight Definition 0 1 Not Used (Always set to 0) 1 2 Device Status Register summary bit. One or more bits are set in the Device Status Register (bits must be “enabled” in enable register) 2 4 Error/Event Queue 3 8 Questionable Status Register summary bit. One or more bits are set in the Questionable Status Register (bits must be “enabled” in enable register). 4 16 Data Available Data is available in the power sensor’s output buffer. 5 32 Standard Event One or more bits are set in the Standard Event register (bits must be “enabled” in enable register). 6 64 Request Service The power sensor is requesting service (serial poll). 7 128 Operation Status Register summary bit. One or more bits are set in the Operation Status Register (bits must be “enabled” in enable register).

42 U2000 Series Programming Guide The status byte enable register (SRE, service request enable) is cleared when you: • cycle the instrument power. • execute a *SRE 0 command. Using *STB? to Read the Status Byte The *STB? (status byte query) command is similar to a serial poll except it is processed like any other power sensor command. The *STB? command returns the same result as an IEEE- 488 serial poll except that the request service bit (bit 6) is not cleared if a serial poll has occurred. The *STB? command is not handled automatically by the IEEE- 488 bus interface hardware and the command is executed only after previous commands have completed. Using the *STB? command does not clear the status byte summary register. The Standard Event Register The standard event register reports the following types of instrument events: power- on detected, command and syntax errors, command execution errors, self- test or calibration errors, query errors, or when an overlapped command completes following a *OPC command. Any or all of these conditions can be reported in the standard event summary bit through the enable register. You must write a decimal value using the *ESE (event status enable) command to set the enable register mask. Table 1-4 Bit Definitions - Standard Event Register Bit Number Decimal Value Definition 0 1 Operation Complete All overlapped commands following an *OPC command have been completed. 1 2 Not Used. (Always set to 0.) 2 4 Query Error A query error occurred, refer to error numbers 410 to 440 in the “Error Message List” in Chapter SYSTem Subsystem. 3 8 Device Error A device error occurred, refer to error numbers 310 to 350 in the “Error Message List” in Chapter SYSTem Subsystem.

1 U2000 Series Programming Guide 43 The standard event register is cleared when you: • send a *CLS (clear status) command. • query the event register using the *ESR? (event status register) command. The standard event enable register is cleared when you: • cycle the instrument power. • execute a *ESE 0 command. Questionable Status Register The questionable status register provides information about the quality of the power sensor’s measurement results. Any or all of these conditions can be reported in the questionable data summary bit through the enable register. You must write a value using the STATus:QUEStionable:ENABle command to set the enable register mask. The questionable status model is shown in the pullout at the end of this chapter. The following bits in these registers are used by the power sensor. 4 16 Execution Error An execution error occurred, refer to error numbers 211 to 231 in the “Error Message List” in Chapter SYSTem Subsystem. 5 32 Command Error A command syntax error occurred, refer to error numbers 101 to 161 in the “Error Message List” in Chapter SYSTem Subsystem. 6 64 User request. 7 128 Power On Power has been turned off and on since the last time the event register was read or cleared. Bit Number Decimal Value Definition

44 U2000 Series Programming Guide Table 1-5 Bit Definitions - Questionable Status Registers The condition bits are set and cleared under the following conditions: Table 1-6 Bit change conditions for Questionable Status Register Bit Number Decimal Weight Definition 0 to 2 - Not used 3 8 POWer Summary 4 to 7 - Not used 8 256 CALibration Summary 9 512 Power On Self Test 10 to 14 - Not Used 15 - Not used (always 0) Bit Number Meaning EVENts Causing Bit Changes 3 POWer Summary This is a summary bit for the Questionable POWer Register. • SET: Error –230, “Data corrupt or stale” • CLEARED: When no errors are detected by the power sensor during a measurement covering the causes given for it to set.

1 U2000 Series Programming Guide 45 Operation Status The Operation Status group monitors conditions in the power sensor’s measurement process. The Operation status model is shown in the pullout at the end of this chapter. The following bits in these registers are used by the power sensor: Table 1-7 Bit Definitions - Operation Status 8 CALibration Summary This is a summary bit for the Questionable CALibration Register. • SET: These may be caused by CALibration[1]:ZERO:AUTO ONCE or CALibration[1]:AUTO ONCE or CALibration[1][:ALL] or CALibration[1][:ALL]?. Error –231, “Data questionable; ZERO ERROR” Error –231, “Data questionable; CAL ERROR” • CLEARED: When any of the commands listed above succeed and no errors are placed on the error queue. 9 Power On Self Test • SET: This bit is set when the power on self test fails. • CLEARED: When the power on self test passes. Bit Number Meaning EVENts Causing Bit Changes Bit Number Decimal Weight Definition 0 1 CALibrating Summary 1 - 3 - Not used 4 16 MEASuring Summary 5 32 Waiting for TRIGger Summary 6 - 9 - Not used 10 1024 SENSe Summary 11 2048 Lower Limit Fail Summary

46 U2000 Series Programming Guide The condition bits are set and cleared under the following conditions: Table 1-8 Bit change conditions for Operation Status 12 4096 Upper Limit Fail Summary 13 to 14 - Not used 15 - Not used (always 0) Bit Number Decimal Weight Definition Bit Number Meaning EVENts Causing Bit Changes 0 CALibrating This is a summary bit for the Operation CALibrating Register. • SET: At beginning of zeroing (CALibration:ZERO:AUTO ONCE) and at the beginning of calibration (CALibration:AUTO ONCE). Also for the compound command/query CALibration[:ALL]?, this bit is set when sensor zeroing begins. • CLEARED: At the end of zeroing or calibration. 4 MEASuring This is a summary bit for the Operation MEASuring Register. • SET: When the power sensor is taking a measurement. • CLEARED: When the measurement is finished. 5 Waiting for TRIGger This is a summary bit for the Operation TRIGger Register. • SET: When the power sensor enters the “wait for trigger” state. • CLEARED: When the power sensor enters the “idle” state. 10 SENSe This is a summary bit for the Operation SENSe Register. • SET: When the power sensor is reading data from non-volatile memory. • CLEARED: When the power sensor is not reading data from non-volatile memory. 11 Lower Limit Fail This is a summary bit for the Lower Limit Fail Register. • SET: If a measurement is made and lower limit test fails. • CLEARED: If a measurement is made and the lower limit test is not enabled or the test is enabled and passes.

1 U2000 Series Programming Guide 47 Device Status Register The device status register set contains bits which give device dependent information. The following bits in these registers are used by the power sensor: Table 1-9 Bit Definitions - Device Status Register The condition bits are set and cleared under the following conditions: 12 Upper Limit Fail This is a summary bit for the Upper Limit Fail Register. • SET: If a measurement is made and upper limit test fails. • CLEARED: If a measurement is made and the upper limit test is not enabled or the test is enabled and passes. Bit Number Meaning EVENts Causing Bit Changes Bit Number Decimal Weight Definition 0 - Not used 1 2 Not used 2 4 Not used 3 8 Power sensor error 4 16 Not used 5 32 Not used 6 64 Not used 14 16384 Not used

48 U2000 Series Programming Guide Table 1-10 Bit change conditions for Device Status Register Bit Number Meaning EVENts Causing Bit Changes 3 Power sensor error • SET: If the power sensor non-volatile memory has failed or other hardwares have failed. • CLEARED: In every other condition.

1 U2000 Series Programming Guide 49 Using the Operation Complete Commands The *OPC? and *OPC commands allow you to maintain synchronization between the computer and the power sensor. The *OPC? query command places an ASCII character 1 into the power sensor’s output queue when all pending power sensor commands are complete. If your program reads this response before continuing program execution, you can ensure synchronization between one or more instruments and the computer. The *OPC command sets bit 0 (Operation Complete) in the Standard Event Status Register when all pending power sensor operations are complete. Procedure • Send a device clear message to clear the power sensor’s output buffer. • Clear the event registers with the *CLS (clear status) command. • Enable operation complete using the *ESE 1 command (standard event register). • Send the *OPC? (operation complete query) command and enter the result to assure synchronization. • Send your programming command string, and place the *OPC (operation complete) command as the last command. • Send the *STB? (status byte query) command to poll the register. This command does not clear the status byte summary register. Examples This example program uses the *OPC? command to determine when the power sensor has finished calibrating. CAL:AUTO ONCE *OPC? MEAS:POW:AC?

50 U2000 Series Programming Guide Saving and Recalling Power Sensor Configurations To reduce repeated programming, up to ten power sensor configurations can be stored in the non- volatile memory. The error list, zeroing and calibration information are not stored. How to Save and Recall a Configuration Power sensor configurations are saved and recalled with the following commands: *SAV *RCL The range of values for in the above commands is 1 to 10.

1 U2000 Series Programming Guide 51 Using Device Clear to Halt Measurements Device clear is an IEEE- 488 low- level bus message which can be used to halt measurements in progress. Different programming languages and IEEE- 488 interface cards provide access to this capability through their own unique commands. The status registers, the error queue, and all configuration states are left unchanged when a device clear message is received. Device clear performs the following actions. • All measurements in progress are aborted. • The power sensor returns to the trigger “idle state”. • The power sensor’s input and output buffers are cleared. • The power sensor is prepared to accept a new command string. NOTE For interfaces the that do not support a low-level device clear, use the ABORt command.

52 U2000 Series Programming Guide An Introduction to the SCPI Language Standard Commands for Programmable Instruments (SCPI) defines how you communicate with an instrument from a bus controller. The SCPI language uses a hierarchical structure similar to the file systems used by many bus controllers. The command tree is organized with root- level commands (also called subsystems) positioned at the top, with multiple levels below each root- level command. You must specify the complete path to execute the individual lower- level commands. Figure 1-9 Hierarchical structure of SCPI Mnemonic Forms Each keyword has both a long and a short form. A standard notation is used to differentiate the short form keyword from the long form keyword. The long form of the keyword is shown, with the short form portion shown in uppercase characters, and the rest of the keyword shown in lowercase characters. For example, the short form of TRIGger is TRIG. Using a Colon (:) When a colon is the first character of a command keyword, it indicates that the next command mnemonic is a root- level command. When a colon is inserted between two command mnemonics, the colon moves the path down one level “B” Subsystem :G :I :H :M :N=:B:H:N “A” Subsystem :D :F :E “C” Subsystem :J :L=:C:L :K

1 U2000 Series Programming Guide 53 in the present path (for the specified root- level command) of the command tree. You must separate command mnemonics from each other using a colon. You can omit the leading colon if the command is the first of a new program line. Using a Semicolon (;) Use a semicolon to separate two commands within the same command string. The semicolon does not change the present path specified. For example, the following two statements are equivalent. Note that in the first statement the first colon is optional but the third is compulsory. CALibration[1]:ZERO:TYPE EXTernal;CALibration[1]:ZERO:AUTO ONCE CALibration[1]:ZERO:TYPE EXTernal;ZERO:AUTO ONCE Using a Comma (,) If a command requires more than one parameter, you must separate adjacent parameters using a comma. Using Whitespace You must use whitespace characters, [tab], or [space] to separate a parameter from a command keyword. Whitespace characters are generally ignored only in parameter lists. Using “?” Commands The bus controller may send commands at any time, but a SCPI instrument may only send responses when specifically instructed to do so. Only query commands (commands that end with a “?”) instruct the instrument to send a response message. Queries return either measured values or internal instrument settings.

54 U2000 Series Programming Guide Using “*” Commands Commands starting with a “*” are called common commands. They are required to perform the identical function for all instruments that are compliant with the IEEE- 488.2 interface standard. The “*” commands are used to control reset, self- test, and status operations in the power sensor. Syntax Conventions Throughout this guide, the following conventions are used for SCPI command syntax. • Square brackets ([]) indicate optional keywords or parameters. • Braces ({}) enclose one or more parameters that may be included zero or more times. • Triangle brackets (<>) indicate that you must substitute a value for the enclosed parameter. • Bars (|) can be read as “or” and are used to separate alternative parameter options. Syntax Diagram Conventions • Solid lines represent the recommended path. • Ovals enclose command mnemonics. The command mnemonic must be entered exactly as shown. NOTE If you send two query commands without reading the response from the first, then attempt to read the second response, you may receive some data from the first response followed by the complete second response. To avoid this, do not send a query command without reading the response. When you cannot avoid this situation, send a device clear before sending the second query command.

1 U2000 Series Programming Guide 55 • Dotted lines indicate an optional path for by passing secondary keywords. • Arrows and curved intersections indicate command path direction. SCPI Data Types The SCPI language defines different data formats for use in program messages and response messages. Instruments are flexible listeners and can accept commands and parameters in various formats. However, SCPI instruments are precise talkers. This means that SCPI instruments always respond to a particular query in a predefined, rigid format. Definition Throughout this document is used to represent ON|OFF|. boolean parameters have a value of 0 or 1 and are unitless. ON corresponds to 1 and OFF corresponds to 0. On input, an is rounded to an integer. A nonzero result is interpreted as 1. Queries always return a 1 or 0, never ON or OFF. Definition Throughout this document is used to represent character data, that is, A - Z, a - z, 0 - 9 and _ (underscore). For example: START and R6_5F. The format is defined as: Figure 1-10 Format of

56 U2000 Series Programming Guide Definition Not a number (NAN) is represented as 9.91 E37. Not a number is defined in IEEE 754. Definition Throughout this document is used to represent numeric information in bases other than ten (that is, hexadecimal, octal and binary). The following syntax diagram shows the standard for these three data structures. For examples, #HA2F, #ha4e, #Q62, #q15, #B01011.

1 U2000 Series Programming Guide 57 Figure 1-11 Format of Refer to section 7.7.4.1 of IEEE 488.2 for further details. Definition Throughout this document is used to denote a flexible numeric representation. For example: +200; –56; +9.9E36. Refer to section 7.7.2.1 of A/a B/b C/c D/d E/e F/f H/h 1 2 3 4 5 6 0 7 Q/q 0 1 # B/b

58 U2000 Series Programming Guide IEEE 488.2 for further details. Definition Throughout this document numeric response data is defined as: Figure 1-12 Format of For example: • 146 • +146 • –12345 Refer to section 8.7.2 of IEEE 488.2 for further details. Definition Throughout this document numeric response data is defined as: Figure 1-13 Format of For example: • 12.3 • +1.2345 • –0.123 Refer to section 8.7.3 of IEEE 488.2 for further details. digit + digit + digit

1 U2000 Series Programming Guide 59 Definition Throughout this document numeric response data is defined as: Figure 1-14 Format of For example: • 1.23E+6 • 123.4E- 54 • –1234.567E+90 Refer to section 8.7.4 of IEEE 488.2 for further details. Definition Throughout this document the decimal numeric element is abbreviated to . For example, , MINimum, MAXimum, DEFault or Not A Number (NAN). Definition Throughout this document is used to represent 7- bit ASCII characters. digit + digit digit + E

60 U2000 Series Programming Guide The format is defined as: Figure 1-15 Format of " " " " " " ' ' ' Program Data Response Data

1 U2000 Series Programming Guide 61 Input Message Terminators Program messages sent to a SCPI instrument must terminate with a character. The IEEE.488 EOI (end or identify) signal is interpreted as a character and may also be used to terminate a message in place of the character. A followed by a is also accepted. Many programming languages allow you to specify a message terminator character or EOI state to be automatically sent with each bus transaction. Message termination always sets the current path back to the root- level.

62 U2000 Series Programming Guide SCPI Compliance Information The power sensor complies with the rules and regulations of the present version of SCPI (Standard Commands for Programmable Instruments). You can determine the SCPI version with which the power sensor’s is in compliance by sending the SYSTem:VERSion? command from the remote interface. The following commands are device- specific to the power sensor. They are not included in the 1999.0 version of the SCPI standard. However, these commands are designed with the SCPI format in mind and they follow all of the syntax rules of the standard. MEMory:CLEar[:NAME] MEMory:TABLe:SELect MEMory:STATe:DEFine MEMory:TABLe:GAIN[:MAGNitude] MEMory:TABLe:GAIN:POINts? MEMory:TABLe:MOVE [SENSe[1]]:AVERage:SDETect [SENSe[1]]:CORRection:FDOFfset [SENSe[1]]:MRATe [SENSe[1]]:POWer:AC:RANGe SERVice:SENSor[1]:CDATE? SERVice:SENSor[1]:CPLace? SERVice:SENSor[1]:SNUMber? SERVice:SENSor[1]:TYPE?

1 U2000 Series Programming Guide 63 Summary of Commands For detail of each SCPI (Standard Commands for Programmable Instruments) command available to program the power sensor, refer to later chapters for more details on each command. All the commands listed also have queries unless otherwise stated in the “Notes” column.

Programming Guide Agilent Technologies 2 MEASurement Commands MEASurement Commands 66 CONFigure[1]? 69 CONFigure [1] Commands 71 CONFigure[1][:SCALar][:POWer:AC] [[,[,]]] 72 FETCh[1]? 74 FETCh[1][:SCALar][:POWer:AC]? [[,[,]]] 75 READ[1] Commands 77 READ[1][:SCALar][:POWer:AC]? [[,[,]]] 78 MEASure[1] Commands 80 MEASure[1][:SCALar][:POWer:AC]? [[,[,]]] 81 This chapter explains how to use the MEASure group of instructions to acquire data using a set of high level instructions.

MEASurement Commands Measurement commands are high level commands used to acquire data. They enable you to trade interchangeability against fine control of the measurement process. The CONFigure, FETCh?, READ? and MEASure? commands all have a numeric suffix which refers to a specific window/measurement. Figure 2- 1 shown an example of the configuration returned result windows. Measurement Command Descriptions MEASure? Provides the simplest way to program a power sensor for measurements. MEASure? is a compound command which is equivalent to an ABORT followed by a CONFigure and a READ?. It does not enable much flexibility or control over measurement settings. CONFigure Used to change the power sensor’s configuration values. CONFigure must then be followed by another command which takes the measurement—for example, a READ? followed by a FETCh?. READ? Takes a measurement using parameters previously set up using either CONFigure or lower level commands. READ? is equivalent to an ABORt followed by an INITiate1 (which performs the data acquisition) and a FETCh? FETCh? Retrieves measurements taken by INITiate*. * INITiate is described in Chapter 11, “TRIGger Subsystem,” on page 261.

67 Figure 2-1 Measurement Display CALCulate Block Window Optional Parameters CONFigure, FETCh?, READ? and MEASure? have the following three optional parameters: • An expected power value • A resolution • A source list Expected Power Value An parameter is only required if you are using an U2000 Series USB Power Sensor. The value entered determines which of the power sensor’s two ranges is used for the measurement. If the current setting of the power sensor’s range is no longer valid for the new measurement, specifying the expected power value decreases the time taken to obtain a result. Resolution The parameter sets the resolution of the current window. This parameter does not affect the resolution of the remote data but it does affect the auto averaging setting. The highest resolution setting is taken to calculate the averaging. If you are making a ratio or difference measurement the parameters are applied to both. Source List The parameter is used to define: • What channels the measurements will be made on, for a dual CONFigure1? current window/measurement

measurement. • Whether the calculation is A- B or B- A, for a two difference measurement. • Whether the calculation is A/B or B/A, for a ratio measurement. The following commands are described in this chapter: Keyword Parameter Form Notes Page CONFigure[1] [query only] page 69 CONFigure[1] [:SCALar] [:POWer:AC] [ [,[,]]] [no query] page 72 FETCh[1] [:SCALar] [:POWer:AC]? [ [,[,]]] [query only] page 75 READ[1] [:SCALar] [:POWer:AC]? [ [,[,]]] [query only] page 78 MEASure[1] [:SCALar] [:POWer:AC]? [ [,[,]]] [query only] page 81

69 CONFigure[1]? This query returns the present configuration of the current window/measurement. Syntax The string returned depends on the setting of the CALCulate:MATH commands. The configuration is returned as a quoted string in the following format: “ ,,” returns the expected value sent by the last CONFigure command or +20 dBm by default. Example ? CONF 1 CONF1? This command queries the configuration of the current window/measurement.

Reset Condition On reset: • The command function is set to :POWer:AC. • The expected power level is set to +20 dBm. • The resolution is set to 3. • The source list on the U2000 Series USB power sensors is set to (@1).

71 CONFigure [1] Commands The CONFigure commands are used on the current window/measurement to set: • The expected power level being measured. • The resolution of the window/measurement. The CONFigure commands do not make the power measurement after setting the configuration. Use READ?, or alternatively use INITiate followed by a FETCh? to make the measurement. The CONFigure command also applies the following defaults to the measurement(s) which are in the current window (the measurement(s) in the window are specified in the parameter): Default Settings Description INITiate:CONTinuous OFF Sets the power sensor to make one trigger cycle when INITiate is sent. TRIGger:SOURce IMMediate When TRIG:SOUR is set to BUS or HOLD, sets the power sensor to make the measurement immediately a trigger is received. TRIGger:DELay:AUTO ON Enables automatic delay before making the measurement. [SENSe[1]]:AVERage:COUNt:AUTO ON Enables automatic filter length selection. [SENSe[1]]:AVERage:STATe ON Enables averaging.

CONFigure[1][:SCALar][:POWer:AC] [[,[,]]] This command is used on the current window/measurement to set: • The expected power level of the measurement. • The resolution of the window/measurement.. Syntax Parameters Refer to “Optional Parameters” on page 67 for additional details on the parameters in this command. Space expected_value DEF resolution , :POW :AC :SCAL DEF source list , CONF 1 Item Description/Default Range of Values expected_value A numeric value for the expected power level. The units of measurement are dBm and W. The default units are defined by UNIT:POWer. Sensor dependent. DEF1 resolution A numeric value for the resolution. If unspecified the current resolution setting is used. 1 to 42 1.0, 0.1, 0.01, 0.001 DEF1

73 1 The mnemonic DEF means DEFault. This is not equivalent to the DEFault parameter used in the command sub-systems. The parameters must be entered in the specified order. If parameters are omitted, they default from the right. The parameter DEFault is used as a place holder. Specifying DEF leaves the parameter value unchanged. 2 When the measurement result is linear this parameter represents the number of significant digits. When the measurement result is logarithmic 1 to 4 represents of 1, 0.1, 0.01 and 0.001 respectively. Example source list The measurement which the command is implemented on. If unspecified the current window setup is used. (@1) Item Description/Default Range of Values CONF1:POW:AC DEF,2,(@1) This command configures the current window/measurement to measure the power of the sensor, using the current sensor range and a resolution setting of 2.

FETCh[1]? The FETCh? queries set the current window’s measurement function. This can be only set to single measurement. They then recalculate the measurement and place the result on the bus. The format of the result is set by FORM[:READ][:DATA]. Refer to Chapter 5, “FORMat Subsystem,” on page 119 for further information. The query returns a measurement result when it is valid. The measurement result is invalid under the following conditions: • When *RST is executed. • Whenever a measurement is initiated. • When any SENSe parameter, such as frequency, is changed. If data is invalid, the FETCh? query is not completed until all data becomes valid. The exceptions to this are, if the power sensor is in the idle state and the data is invalid, or the power sensor has been reconfigured as defined above and no new measurement has been initiated. In such cases, the FETCh? routine generates the error –230, “Data corrupt or stale” and no result is returned. A common cause for this error is receiving a FETCh? after a *RST. If the expected value and resolution parameters are not the same as those that were used to collect the data, error –221, “Settings conflict” occurs. NOTE When TRIG:SOUR is EXT and a new acquisition has been initiated (using the INIT command for example), FETCH? waits until the trigger takes place before executing. If triger conditions are not satisfied - when the trigger level differs greatly from the signal level for example - this can give the impression that the power sensor has hung. To unlock the power sensor and adjust trigger settings, an execute clear (*CLS) must be performed.

75 FETCh[1][:SCALar][:POWer:AC]? [[,[,]]] This command sets the current window’s measurement function with relative mode off, recalculates the measurement and places the result on the bus. The result is a power based measurement and is expressed in the units defined by UNIT[1]:POWer. Syntax Parameters Refer to “Optional Parameters” on page 67 for additional details on the parameters in this command. :POW :AC ? :SCAL Space expected_value DEF resolution , DEF source list , FETC 1 Item Description/Default Range of Values expected_value (for the expected power level) The expected power level parameter can be set to DEF or a numeric value. If a value is entered it should correspond to that set by CONFigure otherwise an error occurs. The units of measurement are dBm and W. The default units are defined by UNIT:POWer. –60 dBm to +20 dBm DEF1

1 The mnemonic DEF means DEFault. This is not equivalent to the DEFault parameter used in the command sub-systems. The parameters must be entered in the specified order. If parameters are omitted, they default from the right. The parameter DEFault is used as a place holder. Specifying DEF leaves the parameter value unchanged. 2 When the measurement result is linear this parameter represents the number of significant digits. When the measurement result is logarithmic 1 to 4 represents of 1, 0.1, 0.01 and 0.001 respectively. Example Error Messages • If the last measurement is not valid error –230, “Data corrupt or stale” occurs. A measurement is valid after it has been initiated. It becomes invalid when either a reset occurs or any measurement parameter, for example frequency, is changed. • If the expected_value and resolution parameters are not the same as the current expected value and resolution setting on the current window, error –221, “Settings conflict” occurs. resolution A numeric value for the resolution. If it is unspecified the current resolution setting is used. If a value is entered it should correspond to the current resolution setting otherwise an error occurs. 1 to 42 1.0, 0.1, 0.01, 0.001 DEF1 source list The measurement which the command is implemented on. If unspecified the current window setup is used. (@1) Item Description/Default Range of Values FETC1:POW:AC? This command queries the current window/measurement result.

77 READ[1] Commands The READ? commands are most commonly used with the CONFigure command to cause a new power measurement to be taken and the result returned to the output buffer. The format of the result is set by FORM[:READ][:DATA]. Refer to Chapter 5, “FORMat Subsystem,” on page 119 for further information. • The READ? query is equivalent to: ABORt INITiate FETCh? or ABORt1 INITiate1 FETCh1?

READ[1][:SCALar][:POWer:AC]? [[,[,]]] This command sets the current window’s measurement function with relative mode off, aborts then initiates the current measurement, calculates the measurement result and places the result on the bus. The result is a power based measurement and is expressed in the units defined by UNIT[1]:POWer. Syntax Parameters Refer to “Optional Parameters” on page 67 for additional details on the parameters in this command. NOTE INITiate:CONTinuous must be set to OFF, otherwise error –213, “INIT ignored” occurs. If TRIGger:SOURce is set to BUS, error –214, “Trigger deadlock” occurs. :POW :AC :SCAL ? Space expected_value DEF resolution , DEF source list , READ 1 Item Description/Default Range of Values expected_value (for the expected power level) The expected power level parameter can be set to DEF or a numeric value. If a value is entered it should correspond to that set by CONFigure otherwise an error occurs. –60 dBm to +20 dBm DEF1

79 1 The mnemonic DEF means DEFault. This is not equivalent to the DEFault parameter used in the command sub-systems. The parameters must be entered in the specified order. If parameters are omitted, they default from the right. The parameter DEFault is used as a place holder. Specifying DEF leaves the parameter value unchanged. 2 When the measurement result is linear this parameter represents the number of significant digits. When the measurement result is logarithmic 1 to 4 represents of 1, 0.1, 0.01 and 0.001 respectively. Example Error Messages • INITiate:CONTinuous must be set to OFF, otherwise error –213, “INIT ignored” occurs. • If TRIGger:SOURce is set to BUS or HOLD, error –214, “Trigger deadlock” occurs. • If the expected value and resolution parameters are not the same as the current expected value and resolution settings on the current window, error –221, “Settings conflict” occurs. resolution A numeric value for the resolution. If it is unspecified the current resolution setting is used. If a value is entered it should correspond to the current resolution setting otherwise an error occurs. 1 to 42 1.0, 0.1, 0.01, 0.001 DEF1 source list The measurement which the command is implemented on. If unspecified the current window setup is used. (@1) Item Description/Default Range of Values READ1:POW:AC? This command queries the current window/measurement.

MEASure[1] Commands The MEASure? commands configure the power sensor to perform a power measurement with the given measurement function, range and resolution then makes the measurement. The format of the result is set by FORM[:READ][:DATA]. Refer to Chapter 5, “FORMat Subsystem,” on page 119 for further information. MEASure? is a compound command which is equivalent to: • The MEASure? query is equivalent to: ABORt CONFigure READ? or ABORt1 CONFigure1 READ1?

81 MEASure[1][:SCALar][:POWer:AC]? [[,[,]]] This command sets the current window’s measurement function with relative mode off, aborts, configures the window, calculates the measurement result and places the result on the bus. Syntax Parameters Refer to “Optional Parameters” on page 67 for additional details on the parameters in this command. :POW :AC :SCAL ? Space expected_value DEF resolution , DEF source list , MEAS 1 Item Description/Default Range of Values expected_value (for the expected power level) A numeric value for the expected power level. The units of measurement are dBm and W. The default units are defined by UNIT:POWer. –60 dBm to +20 dBm DEF1 resolution A numeric value for the resolution. If unspecified the current resolution setting is used. 1 to 42 1.0, 0.1, 0.01, 0.001 DEF1

1 The mnemonic DEF means DEFault. This is not equivalent to the DEFault parameter used in the command sub-systems. The parameters must be entered in the specified order. If parameters are omitted, they default from the right. The parameter DEFault is used as a place holder. Specifying DEF leaves the parameter value unchanged. 2 When the measurement result is linear this parameter represents the number of significant digits. When the measurement result is logarithmic 1 to 4 represents of 1, 0.1, 0.01 and 0.001 respectively. Example source list The measurement which the command is implemented on. If unspecified the current window setup is used. (@1) Item Description/Default Range of Values MEAS1:POW:AC? -70DBM,1,(@1) This command queries the current window/measurement of the sensor, using an expected power level of - 70 dBm and a resolution setting of 1.