Compressor Control System (CCS) | Instrumentation

This article is about COMPRESSOR MAP OF COMPRESSOR CONTROL SYSTEM  and focusing to the engineers, technicians and supervisors. You will find lot of documents related to this article. Just navigate our website  www.paktechpoint.com  and find more articles. Please! Do not forget to subscribe our You tube channel also. Thanks in Advance.

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The Standard Compressor Map is described by polytropic head, Hp, versus actual volumetric suction flow, Qa, and compressor speed, N, You can see in following figure. Depending upon the compressor configuration and instrumentation, changes in molecular weight, temperature, and compressibility are compensated for accurate representation of the compressor operation.

Standard Operating Point

This article is about Surge and Compressor Choke in Compressor Control System  and focusing to the engineers, technicians and supervisors. You will find lot of documents related to this article. Just navigate our website  www.paktechpoint.com  and find more articles. Please! Do not forget to subscribe our You tube channel also. Thanks in Advance.

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Figure shows a simple surge cycle at a constant speed and constant suction pressure. At point 1 of surge cycle we have low discharge point and high flow rate. As the system resistance increases (e.g. discharge valve closes, downstream processes shutdown or decrease load, series units drop off-line, or parallel units come on-line), the compressor flow decreases, and discharge pressure increases.

At point 2 of surge cycle is very near to surge limit and here flow countinues to decreas and discharge pressure will be increase. At point 3 of surge cycle finally stage comes where by due to system resistance compressor can not increase discharge pressure.

If the system resistance increases further, the discharge pressure becomes greater than the machine’s capability. This initiates a surge that spans between points 3 and 4. Flow may actually reverse through the compressor, as shown at point 4. A now reduced system resistance will allow increased flow back through the compressor that brings the operation back to point 2.

SOFTWARE TOOLS IN COMPRESSOR CONTROL SYSTEM

The workstation is capable of the following functions as a minimum: PDW Functionalities

Function                                                                                                                         Software tool
Configuration                                                                                                            Woodward Toolkit
Graphics and display generation and modification                                    GE Proficy iFIX
Control algorithm generation and modification                                         Woodward GAP
Report generation and modification                                                               Microsoft WordPad
Trends generation and modification                                                       Woodward Control Assistant
System access configuration                                                                                Microsoft Windows 7
File access                                                                                                                     Microsoft Windows 7
Backup                                                                                                      Symantec System Recovery Desktop Edition
Logging                                                                                                                              GE Proficy iFIX

The system verifies the operation of the communication channels on a regular basis and alarms on any failure. The system has communication error checking schemes and alarms on repeated failures. The system will periodically test and validate the integrity of the backup communication ports and alarm on any failure.

Time synchronization

The engineering workstations and MicroNet systems synchronize time every 5 minutes, using the Simple Network Time Protocol (SNTP). Within this time the MicroNet System will ensure time accuracy within applicable specifications. MAC shall provide SNTP servers connected to the CCS systems. The accessibility of the SNTP servers shall be provided by MAC.

Redundant CPU Theory

The MicroNet Plus control system uses redundant CPU5200/CPU5200L modules that must be located in the first and last VME slots (A1 and A8 / A14). The chassis has a single motherboard and houses 2 power-supplies, 2 CPUs, and 12 I/O slots. One Single share data path between VME and CPU Modules.
The CPU5200 module offers high processing capability in features like dual Ethernet, dual Real Time Network ports, dual CAN, and a configurable RS-232/RS-422/RS-485 serial port. Module operating temperature limits are –40 °C to +85 °C.
The communication for health between CPU modules do by VME and for control of bus. What is SYSCON, System controller which is in good helath and gain control of IO modules first. The other CPU is always STANDBY. The SYSCON sends all necessary state information to the backup CPU, allowing it to take control of the I/O modules if the SYSCON fails.
The following reasons will cause a failover from the SYSCON CPU to STANDBY CPU:
• CPU module power supplies when fail
• when anything mentioned fail of the processor core, RAM, flash, oscillator, etc.
• If communications fail between the processor and the FPGA.
• A reset of the SYSCON CPU, due to  front panel or remote Resets
• An application requested failover
• An application stop due to any unexpected reason.
• A watchdog timeout between the CPU module and the FPGA. This mean that devices did not respond to the other device within time limit.

Redundant Power Supplies

Two load sharing power supplies provide redundant power to the motherboard, CPU and I/O modules. The MicroNet Plus power supplies are 2-slot wide each and are located at each end of the chassis in the designated PS1 and PS2 slots.

Redundant Inputs and Outputs

Two levels of redundancy are available. The first involves wiring two external input devices to two separate input channels. In the event of a failed sensor or a failure in the connection from the sensor to the control, a valid input is still available

The wiring of  two external input devices to two s I/O modules. Valid input still will be available for system when any sensor fails and
wire signal disconnected.

Redundant Inputs