Control.com - Nerds in Control

In one of my recent power plant projects, I am considering proprietary SG control (mainly BMS from Triconex) and proprietary TG control (GE speedtronics Mark VI) as independent ones. These will be supplied by the main plant (SG and TG) contractor and not part of the station DCS. Balance of the plant (BOP) and auxiliary plant controls will be from station DCS. However our Client intends to operate the entire plant including SG and TG from the station DCS HMI (Single CRT operation). Main plant (SG & TG) supplier confirmed that they will provide OPC server based communication with TCP/IP protocol for third party DCS integration. I am anxious about speed of response of communication for SG and TG control from third party DCS. If you have any experience for similar type of control philosopy, please share the same with me. I need to know whether OPC server based TCP/IP protocol is suitable for control and operation from third party DCS.

Regards,

Amitabha Thakur

We have a similar setup. We use modbus to our Triconex turbine control and GE Excitation systems, but we have wired I/O (some are redundant) to and from DCS for critical signals, like load demand.

This can also be solved with OPC. Matrikon has several customers linking MarkV systems to other systems (bailey systems, Delta Vs, etc.). The solution is an OPC server for Mark V, Matrikon's datamanager, and the appropriate OPC server on the other side.

http://www.matrikonopc.com/opc-drivers/488/index.aspx
http://www.matrikonopc.com/products/opc-data-management/opc-data-ma nager.aspx
http://www.matrikonopc.com/training/opc-hands-on-exercise/setup.htm l

-Sean

If the question is: "Is OPC suitable for process control over Ethernet?" the answer is yes. OPC (OLE for Process Control) has been very successfully implemented for applications just such as this one with satisfactory results at many locations.

Another option you might want to consider since you will be using GE Mk VI SpeedTronic turbine control panels (if you will be using GE turbine-generators for your power island, you will be using Mk VI!) is using Mk VI for the entire balance-of-plant control, including the SG (Steam Generator?) and DCS. Mk VI was designed to be implemented as a balance-of-plant control in addition to being a turbine-generator control system. This was done specifically to address the issue of having multiple control systems and operator interfaces in a single plant.

Using Mk VI for balance-of-plant control would allow you to have one operator interface for the turbine-generator control, SG control, and DCS control, and to reduce the number and stock of spare parts (since many cards/modules/cables, etc. are shared by the turbine-generator and balance-of-plant Mk VI control systems). There would be no OPC server/client to set up and maintain or troubleshoot.

No; this author doesn't work for GE. This is simply a recommendation made to suggest an option that may not have been considered which would reduce overall plant complexity--and alleviate the concern about the OPC interface.

markvguy

OPC is the best option for single dashboard operation. OPC is definitely fast enough to get the DISPLAY data to the operators.

However, I would not use OPC in closed loop CONTROL. That is, if there are any CONTROL or SAFETY signals to and from the DCS, then do that using conventional hardwire or Modbus.

For all flavours of OPC and other automation software technologies take a look at the book "Software for Automation: Architecture, Integration, and Security". http://www.isa.org/autosoftware

Jonas Berge SMAR
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jberge@smar.com.sg
www.smar.com
Learn fieldbus and Ethernet at your own pace: www.isa.org/fieldbuses
Learn OPC and automation software at your own pace: www.isa.org/autosoftware
Jonas Berge SMAR