Ingersoll-Rand CENTAC Technical Reference Manual

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 Copyright Notice Copyright 1996-1999 Ingersoll-Rand Company THIS MANUAL IS SOLD "AS IS" AND WITHOUT ANY EXPRESSED OR IMPLIED WARRANTIES WHATSOEVER. Printing Date: 18 October, 1999 Ingersoll-Rand air compressors are not designed, intended, or approved for breathing air applications. Ingersoll-Rand does not approve specialized equipment for breathing air applications and assumes no responsibility or liability for compressors used for breathing air service. ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 Table of Contents What’s New In This Manual_____________________________________________ 1 References __________________________________________________________ 2 General - CMC Panel __________________________________________________ 3 Control Methodology __________________________________________________ 4 Performance Control ________________________________________________________4 Unload _____________________________________________________________________________ 4 Constant Pressure Control - Modulate _______________________________ ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 Loading____________________________________________________________________________ 18 MinLoad, Loaded, Full Load and MaxLoad________________________________________________ 18 Unloading __________________________________________________________________________ 18 Coasting ___________________________________________________________________________ 18 Compressor Operating States _______________________________________________19 User Interface _______________________________________________________ 20 OUI (Operator User Interface) _________ ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 Troubleshooting Example ___________________________________________________45 Input/Output (I/O) System ___________________________________________________46 Vibration Monitoring System (VMS)_____________________________________________________ 46 Checking Vibration Transmitter Power_______________________________________________ 47 Checking Vibration Circuit ________________________________________________________ 47 Check the Vibration Probe, and Cable_______________________________________________ 48 Checking the Vibration Probe_______ ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 Vortex Tube Cooler __________________________________________________________________ 73 Type Z Purge _______________________________________________________________________ 73 Fused Control Power Disconnect _______________________________________________________ 73 Control Electrical Package __________________________________________________74 Stage Data Package ________________________________________________________74 Alarm Horn ________________________________________________________________74 Running Unloaded Shutdown Timer _________ ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 MODBUS Messages _________________________________________________________________ 86 Device Address ___________________________________________________________________ 86 Function Code ____________________________________________________________________ 86 Data Addresses___________________________________________________________________ 86 Single Module Addresses_________________________________________________________ 87 Multiple Module Addresses _______________________________________________________ 87 Data ____________________________ ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 CMC as PLC5 ___________________________________________________________________ 110 CMC as SLC5/04_________________________________________________________________ 111 Data File Addressing for PLC5/SLC504_______________________________________________ 111 CMC Data Addressing_____________________________________________________________ 112 Supported Functions ________________________________________________________________ 116 Command 0F/Function 68 - PLC5 Typed Read_________________________________________ 116 Example: Reading an Analog ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 Module Layout _____________________________________________________________________ 140 Connector Description_______________________________________________________________ 140 Connector Input and Output (I/O) ______________________________________________________ 140 CMC User Interface/Bezel Cleaning Instructions __________________________________________ 141 Backlight Replacement Procedure _____________________________________________________ 141 Universal Communication Module (UCM) Optional_____________________________144 Module Layout ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 Table of Figures Figure 1: Compressed Air System ........................................................................................................4 Figure 2: Autodual Control....................................................................................................................5 Figure 3: Modulate Control ...................................................................................................................5 Figure 4: Performance Control ....................................................................... ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 1 What’s New In This Manual This is the third version of the CMC Manual. This version was created to support new features incorporated into the CMC Product, and provide additional information in general compared with the first and second versions. Specifically, new features are as follows: 1. The basic compressor control logic has been refined to give even better pressure control than before. 2. Surge AbsorberTM. This feature replaces Surge Reload and reduces the magnitude and duration of pressure variations for a surge cycle. 3. Gas an ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 References The following references were used in creating this document. All of this documentation is recommended for a more detailed understanding of specific control modes and control panel functions. NEMA STANDARDS PUBLICATION NO. 250, Enclosures for Electrical Equipment (1000 Volts Maximum), Revision 2, May 1988 NFPA 496 Standard for Purged and Pressurized Enclosures for Electrical Equipment, 1986 Edition Nisenfeld, A. Eli, Centrifugal Compressors: Principles of Operation and Control, Instrument Society of America, 1982 Moore, Ralph ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 3 General - CMC Panel The CMC panel is the microprocessor-based control and monitoring system for Centac and X-FLO centrifugal compressors. The CMC handles all pressure control and monitoring functions; as well as, control auxiliary equipment such as the main motor starter, oil heater, and prelube pump. The CMC panel has a custom designed computer board called the Base Control Module (BCM). This board has a microcontroller and memory chips that tell the rest of the panel what to do for the various input pressures, temperatures and vibrati ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 Control Methodology The CMC utilizes performance and surge control methodologies to meet varying compressed air system needs. The term "performance control" is used for grouping the control modes that affect compressor power consumption through movement of the intake and discharge valves. Performance Control The CMC has three standard performance control modes or methods of operation. These modes are Unload, Modulate and Autodual for typical plant air compressors operating in constant pressure applications. For the discussions that foll ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 5 Once loaded, the compressor will operate along the constant pressure line until the user switches to Unload or presses the stop button. Control is accomplished by modulating the inlet valve within the compressor's throttle range. When system demand is less than the minimum throttled capacity, the discharge pressure is maintained by modulating the bypass valve and venting some or all of the air to atmosphere. This valve is opened just prior to reaching the surge line. Whenever the bypass valve is open, the inlet valve maintains its posit ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 Autodual automatically unloads the machine when the bypass valve is opened beyond the Unload Point for a programmed time period called the Unload Delay Time. The Bypass Valve Unload Point is selected to correspond with the check valve closing since at this point the machine is not supplying the system (Figure 1). The Unload Delay Timer should be set to prevent unloading during short excursions through the Unload Point. The Reload Percent determines the System Pressure at which the machine will automatically load into the system. How doe ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 7 Proportional Band Proportional control varies the signal sent to the valves as a linear response to the difference between the actual system pressure and the system pressure set point. Valve responsiveness can be adjusted through the CMC with the proportional band, Pb, set point. This scaling factor, graphically depicted in Figure 5, is the amount of change in the input variable (actual minus set point pressures) to cause a full scale change in the output variable (valve position). In other words, if the pressure in the air system fluct ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 Figure 6 shows the relative valve response over time for two combinations of Pb and It. As shown, when Pb is low and It is fast, valve activity is significant in both magnitude and frequency to obtain the desired set point. The other scenario, Pb is high and It is slow, has relatively little valve activity, and may never reach the set point position. Proportional Band and Integral Time are variables used internally by the control system to determine valve response and direction for a given compressed air system. Each has an optimum valu ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 9 Capacity - Mass Flow Power at Coupling Amps Discharge Pressure TL HLL Inlet Valve MaxLoad PID Control Zone Inlet Valve MinLoad PID Control Zone Inlet Valve Pressure PID Control Zone Bypass Valve Pressure PID Control Zone controlling pressure. This point is called MinLoad or Throttle Limit (TL). The location of these two points is graphically depicted on the pressure and power versus capacity curves as shown in Figure 7. MaxLoad or High Load Limit (HLL) setpoint, in units of amps, is a parameter entered into the CMC that prevents the ma ...

1X36003 Version 2.52  1996-1999 Ingersoll-Rand Company Date of Issue: 18-Oct-1999 The following table presents seven capacity requirements for a plant air system. At each of the capacities, the table shows the compressor output, valve position, discharge pressure and power. Each of these values represents a percentage and is only an example. P2 is the specified discharge pressure and P0 is the barometric pressure. From the table above, once the system required capacity moves below 75 percent, the compressor still produces 75 percent capacity with 80 percent of the power. If the system needs only 25 percent capacity, ...