Hi,

Siemens PCS7: Does it have the features to be called as a true DCS or is it a good PLC??? Also can it be compared with Yokogawa CS3000, DeltaV, Honeywell or ABB AC800M. Need some suggestions.

Thanx,
Anil

 

Sure it is a real DCS system like the competition you mentioned. They have Full Redundancy all levels so I would say that it is a true DCS with a lot more functionality that the standard DCS.

 

PCS7 is truly a PLC/Scada system. However, the functions and architecture are the same as a DCS. In fact, it is very hard to find the differences between the latest DCSs and PLCs in the recent past.

We are curently comparing DeltaV, Experion and PCS7. We are having a hard time finding differences that really make one stand out as being the best.

In the end, we are recommending DeltaV, but only due to our existing installed base for the majority of the plants. We could not find any great benefit of one over the other.

One reason we leaned away from Siemens is their Batch is very new and we did not want to be the guinea pigs.

 

If you want comparision about DCS/PLC, we can
help you in this matter, but definite I/O counts
& architecture you are proposing is very important.

But you missed true DCS - Invensys Foxboro I/A
system.

Regards

Jari
[email protected]

 

A true DCS is built for reliability, without complicating things.
- Dual redundancy
- No server based project software
- Single database.

Try this exercise. Compare the price of a Yokogawa CS3000 DCS controller, fully dual redundant ( model AFS50D ) to the price of a fully dual redundant PCS7 controller.

 

I would agree with a lot of what is being said here. PCS7 has all the functionality of traditional DCS systems (and much more). Regarding the Batch software comments, I was working with the PCS7 Batch in the US in year 2000 on a pseudo-development project. Since that time, there have been many large installations using Batch and it works quite well...

 

Hi,

Any good DCS allows new control, I/O configuration and HMI to be developed, tested and downloaded/made live without resarting the controller. In fact some only have an on-line mode for all changes. Not sure sure that Siemens PCS7 can actually do this.

Mikho

 

So far I have seen several excellent criteria for a good DCS system.

But we should consider:

* SCALEABILITY

1. How scaleable is the system? How big can the system get without running into performance issue? For a large refinery or a LNG plant with geographical expanse, a big DCS system is more desirable than a group of small DCS sytems.

* TOTAL INSTALL COST, a lot of which is engineering cost

2. How easily it allows collaboration between many engineers working on the job? Does it have a central database that allows multiple concurrent accesses to allow rapid development?

3. Does it let you simulate the hardware to eliminate the need to be at separating staging location and away from your office?

ONLINE MIGRATION & FOREVER SUPPORT

4. Pro-longed downtime of certain plants cost the process owner more than the DCS itself, so sometimes this is the most critical criteria in selecting the DCS.

NATURAL DIASTER SUPPORT

5. If natural disasters, such as hurricanes or floods destroy your equipment, can your DCS vendor replace your entire system in matters of weeks or even days? Do they have the capability to restore the configuration of the system in a relatively short time?

ADVANCED CONTROL SUITE

6. Now that your plant is up and running, how to you optimize it? How do you manage your alarms more intelligently? How do you ensure that operators follow operations procedures correctly to prevent pilot errors? How do you distribute your current process views with the finance folks? How do you analyze production trend?

These questions should be added to the questionnaire when comparing true DCS's. A few of process owners can afford not having these issues, but most them will have to think about these things to make that they get the most out of their sizable investment.