Field Bus Connectivity with Yokogawa Centum CS DCS

  • Thread starter Mihir Ramkrishna
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Thread Starter

Mihir Ramkrishna

We are expanding the capacity of our plant. We will be installing new vessels and colummns for this purpose. We have Yokogawa Centum CS DCS commissioned in 1999. We are thinking of considering Fieldbus for the new instruments

I would like to know if anyone has implemented fieldbus integration with Centum CS. What was the methodology adopted? What hardware would be required for it? We are considering a hazardous area, so what would be the maximum number of instruments that can be connected to on ACF11 card? Is it possible to get data from other non yokogawa system over RS232 for Yokogawa centum CS DCS. We considering only open loop applications for the while.

If anyone can give be a cost comparison of the field bus v/s conventional multiplexed hardware used in the Centum CS DCS, it will be great.


Your input can be summarized to two questions:
1. Using ACF11 to interface FF devices

Unless you have some clear concept of your requirements, don't go for FF. It is not worth the troubles you have to go through.

2. Can external devices be interfaced to Centum.

The answer is "Yes". The communication modules ACM11 and ACM12 can be used to interface subsystems. These two modules support a wide range of protocols - MODBUS, AB etc (to name a few).


Hello Mihir,

Mr. Radhakrishnan have already given some points to your query, I'd like to add the following:

1] Hazardous area, is it Zone 1, IIA, IIB or IIC? Are you planning to have field maintainance for
xtrs? Then you might require FISCO approved.

2] It may be possible you might have to upgrade the firmware of CS3000 to CS3000R3 to have support
available for FF.

We have implemented various FF projects with other
system & we can be helpful to you.


iconcnl @ vsnl. net

Mihir Ramkrishna

I will be obliged if some one can provide me with a cost comparative account of the FF vs the conventional method of tags connected to Centum CS DCS.
In general, plants have reported many savings in both time and money using fieldbus. See here for example (make sure to get full link from http to =1)...

For an FF project to be a success it has to be planned, engineered, and designed correctly. If you follow old DCS practices for design, loop check, commissioning, etc. all you will get is a more expensive DCS without new fieldbus benefits. However, if done correctly FF will deliver on the great promise of digital control and architecture. These practices have been worked out and fine tuned by leading automation vendors over thousands of projects the past ten years.

FF provides two classes of savings:
* Project
* Operations

How each technical feature of FF technology is used to create product features that are used to change work practices that translate into reduced time and cost is a long story. Too long for a forum post. But here is a summary of it all:

- Less wires, conduits, trays, terminations
. Multiple devices per bus
. Multiple signals per device
- MOV, MV, feedback etc.
- Reduced control room footprint
. Fewer I/O cards and barriers
- Fewer engineering drawings
. Multiple loops per drawing
- Faster loop check and commissioning
. Automatic 'ring-out'
- Enables innovation...
. New classes of digital devices

Operation & Maintenance
- Better accuracy
. No precision lost in D/A & A/D
- High signal integrity
. Distortions can be detected
- More powerful diagnostics
. More current for devices
- Engineering unit
. Measure to sensor limits
. No range mismatch
- Stave off obsolescence
. Firmware download
- Easier device troubleshooting
. Remote Diagnostics
- Validity display and loop shut-down
. Signal status
- Predictive maintenance
. Diagnostics Alerts
- Easier replacement and servicing
. Fewer Connections

Again, FF has come along way over the past ten years. The specifications have been clarified, corrected, and complemented. Product implementations of the technology have been corrected and completed. Better tools have come to
market. Procedures for project execution and practices for operations and maintenance have been established. It is far easier to be successful now
than only a few years ago. Most major EPCs now have FF experience.

You are asking about the ACF11 which is part of the RIO system which I have never used. Yokogawa also has an FIO system which I have used extensively. It has good Foundation Fieldbus support and it has good support for other communications networks such as RS232, RS485 and Ethernet. Various protocols are available.

I had a business partner who installed Foundation Fieldbus on an RIO system and had a difficult time with it. I don't know if the difference is because of the IO style or because of the early implementation of Foundation Fieldbus. Now, when we install Foundation Fieldbus instruments, things are better.

Radhakrishnan and Berge are correct. listen to them and be thorough in your design.

There are a several companies that produce the connecting devices for Foundation Fieldbus installations. For an example, the MTL-Relcom website has good information about installation in hazardous areas.