If a plant is operating satisfactorily in the realm of single loop control philosophy with electronic instrumentation and you are intending to gallop towards DCS, the question you often may come across would be, why go for such an investment?

This is the same situation as being struck in the cross-roads where you can see four paths not knowing where they lead to!

If someone can help take me out of this convincing fuss with some crisp suggestions that are at the same time easily digestable for the troubling souls, I'll be obliged for anyone's pertinent help!!!!

 

Which make single loop controllers ?
What is input/output ?
Type of plant ?

Jari
[email protected]

 

Hi Rana,

Let me put my observations into words. A plant can very well run with single loop electronic controllers and instrumentation. But a DCS can bring you following advantages:
1. Ease of operation - overview of plant process on a single screen, operation from a single terminal, remote operation of plants located at distant location.
2. Process analysis - complex tools for trend analysis, data representation, etc.
3. Complex control - for better control over process, complex algorithm can be implemented - may result in more production
4. Data History - Process parameters can be stored for future analysis, reports, etc.
5. Automatic Report and log generation
6. Alarms and events generation
7. Operators action log
8. Integration to Management Information System for Enterprise Resource Planning and other buzz words.
9. More Reliable due to availability of Hot Standby Controllers and communication
10. I/O redundancy is also possible
11. Sequence of event recording is also possible to resolve simultaneously happening events.
12. Some products offer remote diagnosis, etc. which is otherwise not possible.
13. Ease of maintenance - hot replacement of components
14. Ease of up-grading - hot up-grading of OS etc.
15. Ease of programming and reconfiguration
16. Saving of power and energy - more components - more power!
17. Saving in installation cost - DCS are fieldbus compatible, cabling cost can be saved. Maybe removing old cable and selling it for metal brings you good returns as metal cost has gone high like anything in the recent past!

There are many more advantages. Broadly speaking, it helps to understand and operate your process better. If your plant can operate with large downtime, less analysis, less control over process and you can afford to do so, but see that you are not losing your business. Low cost alternatives to DCS can be PLC with SCADA or PAC, etc.

Regards,

C. Potdar