What are the main strengths and pitfalls in leading DCS technologies in India? I usually come across multinationals like Honeywell, Emerson, Yokogawa... Are there any good Indian service providers in this segment?

Also, DCS technology has been around for almost 25 years. Is it still the best control technology, or are there better alternatives in the market today? I read recently about PAS - process automation systems replacing DCS as the basic process control in some cases - comments?

 

Hi,

DCS are in demand still in all the large automation requirement. Even though it was introduced long back but all the manufacturers like Honeywell, Yokogawa, Emerson etc are keep on upgrading their hardware, communication & software which meets today's market demands. For Example, some of the improvemnets are Field BUS technology I/Os, Ethernet communication etc

Nowadays most of the customers prefers DCS even for the smaller applications (typically 1000I/O) so that the same can be extended later if required & easy of use. PACs are mostly used for smaller application & it used only for alternative of PLCs

Hope you hv some clarity on this

Regards,

 

As much as I know all the DCS manufacturers are multinational vendors and manufacturers. These hi technology systems are popular and worldwide installed. Well, no software system is bug free (as much as I know) so, one or the other problem occur now or later. I seriously doubt their testing procedures before launching them to market. Adding to that, many times local country representatives replace the standard company product from the cheap products which they can get from local market like prefeb. cables, connectors, relays etc. which hamper the smooth running of the system.

Moreover, the quality of the system depends upon how well you have engineered and commissioned the system which is very important part for the smooth running and wellbeing of the system.

I have worked with two leading DCS manufacturers.
Need any more clarification ?

 

Hi,

in our 15 MW power plant we are having siemens DCS and we have snider PLC in our coal washing plant and in our sponge iron plant. as far as i observed ,the activities possible in DCS are possible in PLC also (ex-trends, alarms, ligics, parameter value tables, print outs, etc). the only difference is the I/Os are more in DCS when compared to PLCs. And i have asked the representatives of DCS manufacturers like ABB, YOKOGOWA etc to clarify the difference between DCS and PLC SCADA combination, but i could not get clear information. Can you please clarify this.

Sriram

 

PLC's were designed to replace complicated and cumbersome electrical relay based system with electronic component system. They were subjected to some specific task only. The purpose of the DCS was to bring the big system with smaller sub systems into centralized control, hence greater efficiency, better supervision etc. in a bigger plant using a distributed architecture.

Now a days,multiple PLC's can be made to work in a distributed architecture as there had been lots of improvements in electronics and softwares. They have speed, communication ability, large I/O handling capacity, better reporting, fault analysis etc which is as good as any DCS in the market.

So, you can see there is only conceptual difference which is left. DCS works in distributed architecture while PLC's are generally used for some specific application only. Well, there are certainly some commercial and technical aspects while choosing PLC or DCS for any application.

In general you may check:
www.wikipedia.org
this may give you some historical insight.

There had been a discussion on "which is the best DCS" in this forum some time back. Try to get it from the history. Interesting read.