DCS selection procedures


Thread Starter

Zalo Shulimovitch

We are in the stage of selecting a DCS system.
Some years ago was a organization that was doing comparison between
different DCS suppliers
with tips of how to select the best one
Can anyone help me with the name of some Body/Authority that is doing
unbiassed comparations?
Zalo Shulimovitch

Paul Gruhn, P.E. Moore Process Automatio

I suggest you buy "Understanding Distributed Processor Systems for Control"
by Sam Herb, and published by ISA.

Nilanjan Mukhopadhyay

I think that one first have to understand his /her own requirement
very nicely before selection of such equipment . Otherwise a very nice
system may be simply sitting idle or a too tight system may hardly be able
to do the requirement . I personally have had experience of at least one
extreme . Before you really start evaluation try to think layer wise
requirement : Plant : Integration: Business :... . You also look into the
probable MMI requirement as well as 3rd party integration. Think about the
interoperability of the Tx end . There are many things really to speak .But
do not put much value on the evaluation published by independent companies. It may be better if you communicate with the users of the same system +
same series.

Gene Giltner


Control magazine did some work in DCS comparison. We helped write the evaluation. If you still need help give us a call.

Gene Giltner

Patrick Viskens

Hi All,

Before starting any selection of a DCS system please define the objectifs you want to achive. Make a clear specification of the functionality which you desire. When making the basic specifications for your control system take also
in account that beside DCS systems these days also contain al lot of possibility's such as ERP, Maintenance , Management information , advanced control , SAP-link , ....and so on.

During the selection use your basic requirement as a guidance. Don't choose a DCS system only based on the offer made by the suppliers. Take
also in account following items :

- Easy to use , all nessesary tools are available
- Easy to simulate the I/O to FAT engineering work
- Good engineering tools
- Make a study of the total cost of ownership once the system is up and running
- Service capability's of the suppliers
- State of the art but proven technology.
- ...

These where some points that crossed my mind when reading the mail and I hope that they are of some help to you .

Ing. Patrick Viskens
Automation Engineer
E-mail : [email protected]
I doubt ISA will help you. They sleep so long on the switch. I hate ISA twice than I like. Their lack in ingeniosity is their mark of commerce.
I found their symbology for DCS functions so degrading. All their square circles are like them drilling square before round and they want you to beleive they are gospel.
Years ago, I was very highly paid doing DCS specifications for clients. The most difficult part for most evaluators remains to be of no commerce (no subjectivity, be flat...). It's a learning process to read between lines of specifications. Their limits and bugs is of utmost interest, costwise in the future.
Also remember that some system were designed by one client for himself first. It may not be suitable to you.
Some user require little extra capability, so they are happy. Progressive integration may be important. If your existing system is an aged wine, check the field instruments to be renewed
as well.
Flexibility in software/hardware should put you on the safe side, bearing in mind optimisation.
I'm saying that because they will all pass the entry quiz of your process control spec.

Mourad Tandjaoui

Hello, I totally agree with Nilanjan. For a particular site, there are probably several "technically suitable" systems. However, a certain number of other factors must be considered. In our case (we have installed 5 systems some of them being amongst the largest in the world), an important criteria was technical vendor support. This is not as obvious as it seems. Vendors are very keen on selling a systems, but not all of them can garantee a full support once the system is installed. Especially if you're in a remote location around the world. Also, nowadays, things like system openess, and "evolutivity" are very important. One has also to be carefull with sizing of the system. Their complexity helps the vendor to hide the weaknesses and helps them to "play" with some parameters to be competitive. Some of these parameters are not always fully understood by buyers. Mourad. Algeria.