Measurement Computing USB-1608FS Operation & User’s Manual

Document Revision 7A January 2014 © Copyright 2014 User's Guide ...

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Preface About this User's Guide ....................................................................................................................... 5 What you will learn from this user's guide ......................................................................................................... 5 Conventions in this user's guide ...................................................................................................... ...

4 Microcontroller ................................................................................................................................................. 22 Power ................................................................................................................................................................ 23 General ........................................................................................... ...

What you will learn from this user's guide This user's guide describes the Measurement Computing USB-1608FS data acquisition device and lists device specifications. Conventions in this user's guide For more information Text presented in a box signifies additional information and helpful hints related to the subject matter you are reading. Caution! Shaded caution statements present information to help you avoid injuring you ...

The USB-1608FS is an analog input and digital I/O data acquisition device providing the following features:  Eight 16-bit single-ended (SE) analog input channels Each input channel has a dedicated A/D converter for simultaneous sampling. Software-selectable analog input ranges of ±10 V, ±5 V, ±2 V, and ±1 V  Eight individually configurable digital I/O channels  One 32-bit event counter  One external di ...

What comes with your USB-1608FS shipment? The following items are shipped with the USB-1608FS. Hardware  USB-1608FS  USB cable Software  MCC DAQ CD Documentation In addition to this hardware user's guide, you should also receive the Quick Start Guide. This booklet provides an overview of the MCC DAQ software you received with the device, and includes information about installing the software. Please read this ...

8 If the LED turns off If communication is lost between the device and the computer, the device LED turns off. Disconnect the USB cable from the computer and then reconnect it. This should restore communication, and the LED should turn on. Calibrating the hardware You can calibrate the USB-1608FS with InstaCal. Perform calibration whenever the ambient temperature changes by more than ±10 °C from the last calibration. The Measureme ...

The USB-1608FS can acquire analog input data in three modes – software paced, hardware paced, and BURSTIO. Software paced The USB-1608FS acquires data one analog sample at a time using software-paced mode. You initiate the A/D conversion by calling a software command. The analog value is converted to digital and returned to the computer. You can repeat this procedure until you have the total n ...

10 External components The external components – screw terminal banks, LED, and USB connector –are shown in Figure 2. 1 Screw terminal pins 21 to 40 3 Screw terminal pins 1 to 20 2 LED 4 USB connector Figure 2. USB-1608FS components USB connector The USB connector provides +5 V power and communication. No external power supply is required. LED The LED indicates the communication status; it cannot be disabled. LED states are list ...

11 Use 16 AWG to 30 AWG wire when making connections to the screw terminals. Pinout locations are shown in Figure 3 below. Figure 3. Screw terminal pinout Signal connections Analog input You can connect up to eight analog input connections to CH0 IN through CH7 IN. Connect unused analog input terminals to ground terminals during operation. For example, if you are not using terminal 15 (CH7 IN), connect this terminal to terminal 16 ( ...

12 Channel-Gain queue The channel-gain queue feature allows you to configure a different gain setting for each analog input channel. The gain settings are stored in a channel-gain queue list that is written to local memory on the device. The channel-gain queue list must contain all eight channels listed in consecutive order. An example of the channel-gain queue list is shown in the table below. Sample channel-gain queue list Element ...

13 The user-configurable jumper is labeled DIO. Figure 5 shows the location of the jumper on the circuit board. Figure 5. Pull-up/down jumper location 5. Configure the jumper for pull-up or pull-down, as shown in Figure 6. Figure 6. Pull-up/down jumper configuration 6. Replace the top section of the housing, and fasten it to the bottom section with the three screws. For more information on digital signal connections For general info ...

14 Ground The analog ground (AGND) terminals provide a common ground for all analog channels. The digital ground (GND) terminals provide a common ground for the digital, trigger, counter, sync and power terminals. Power output The PC +5V terminal is a 5 volt output that is supplied by the computer. You can use this terminal to supply power to external devices or circuitry. Caution! The PC +5V terminal is an output. Do not connect to ...

15 Figure 7 shows an ideal, error-free, USB-1608FS transfer function. The typical calibrated accuracy of the USB-1608FS is range-dependent, as explained in the "Specifications" chapter. We use a ±10 V range as an example of what you can expect when performing a measurement in this range. Figure 7. Ideal ADC transfer function The USB-1608FS offset error is measured at mid-scale. Ideally, a zero volt input should produce an output co ...

16 Figure 9. ADC Transfer function with gain error For example, the USB-1608FS exhibits a typical calibrated gain error of ±0.04% on all ranges. For the ±10 V range, this would yield 10 V × ±0.0002 = ±4 mV. This means that at full scale, neglecting the effect of offset for the moment, the measurement would be within 4 mV of the actual value. Note that gain error is expressed as a ratio. Values near ±FS (±10 V) are more affect ...

17 Synchronized operations You can run up to two USB-1608FS devices on most computers. You can connect the SYNC pin of two devices together in a master/slave configuration and acquire data from the analog inputs of both devices using one clock. When the SYNC pin is configured as an output, the internal A/D pacer clock signal is sent to the screw terminal. You can output the clock to the SYNC pin of a second device that is configured ...

18 Mechanical drawings Figure 11. Circuit board (top) and enclosure dimensions ...

Typical for 25 °C unless otherwise specified. Specifications in italic text are guaranteed by design. Analog input Table 1. Analog input specifications Parameter Condition Specification A/D converter type 16-bit successive approximation type Number of channels 8 single-ended Input configuration Individual A/D per channel Sampling method Simultaneous Absolute maximum input ...

20 Table 3. Accuracy components - All values are (±) Range % of Reading Gain error at FS (mV) Offset (mV) ±10 V 0.04 4.00 1.66 ±5 V 0.04 2.00 0.98 ±2 V 0.04 0.80 0.51 ±1 V 0.04 0.40 0.28 Table 4 summarizes the noise performance for the USB-1608FS. Noise distribution is determined by gathering 50 k samples with inputs tied to ground at the user connector. Samples are gathered at the maximum specified sampling rate of 50 kS/s. Ta ...