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Siemens PCS7
Could any one suggest me how reliable Siemens PC7 DCS is??

Hi All,

Could any one suggest me how reliable Siemens PC7 DCS is?? In fact when I was checking this site, there was an message from Anonymous on July 1st stating that he has faced hell lot of problems with Siemens PC7 System & wanted to migrate to DeltaV. Since we had already placed order on Siemens PC7 DCS for Complete Redundant System, I am little afraid now. Can any one just suggest me the reliability & performance of PC7??


If you've read some of the other posts where people have asked about one PLC vs another or DCS vs another, you will have noticed that the overwhelming consideration when purchasing a PLC or DCS is the knowledge and experience of the control system integrator/supplier.

Any PLC or DCS can be extremely reliable and trouble-free in one application, and less than a mile down the highway the same (slight difference in software/hardware version model number, for example) package can be just a terrific maintenance headache.

The differences are usually related to the installation, the configuration, the care (or lack thereof) which was taken with the routing and installation of the interconnecting wiring and placement of the I/O, and the knowledge and experience of the programmers and commissioning personnel.

In this author's experience, configuration, interconnection (signal level isolation, shield grounding practices), and application (programming, redundancy where appropriate), and configuration (jumpers, hardware keys, software settings, and PID loop tuning) are all more important than the choice of hardware or manufacturer.

Some AutomationDirect and Omron installations have been more robust and reliable than some Siemens and Fisher-Rosemont/Delta V installations on the same site--it all had to do how the set-up, configuration and programming, installation (wiring, I/O placement), and commissioning was done.

Siemens make some fine hardware and software. Some people have only had good experiences with it; others have only had bad experience. The same can be said of A-B or Omron or GE-Fanuc or Delta V hardware and software.

The real variable is not the choice of hardware and software--it's the choice of the individual or firm who will be responsible for the application of the chosen hardware/software. The real question is: What is the knowledge and experience of the firm you have contracted to configure, program, and install the hardware and software you have chosen?

You would do better asking previous clients of the control system integrator whether or not they were satisfied with the reliability of the "end-product" they received. But it sounds like it's a little late for that....

Many of the responses you will likely receive here will be of the nature that the respondent found this equipment or that equipment to be easier to configure or troubleshoot. Very few people have responded with reliability issues (other than the post you cited).

This author has seen many different control systems criticized because of extremely poor programming. On more than one site, the starting of every pump or fan or blower was annunciated as an alarm--a process alarm! Rather than alarm when the pump or fan or blower didn't start when commanded to, the programmer chose to generate an alarm to indicate the "event" of a pump or fan or blower starting. The operators, not knowing how to filter or disable the offensive motor starting "alarms" just began to ignore most alarms--and the control system (DCSs in these cases) got all the blame. Not the control system integrators, but the control systems.

Other installations used improper control system hardware to drive high-wattage motor starters and solenoid-operated devices. Fuses and printed circuit cards were continually being replaced--and the control systems were labelled as unreliable.

Nearly non-existent these days with the use of fiber-optic cabling was the problem of communications between remote I/O racks. If not properly routed, these copper cables can pick up a lot of induced voltages, and some of the comm modules can handle a certain amount, some can't tolerate any. This was a real problem for years, and gave many control systems a bad reputation--again, not the control system integrator or the installer, but the control system got the blame.

All of these sites used hardware and software provided by major manufacturers. In some cases, there were other installations of similar hardware and software elsewhere on the same site (refinery, plastics plant, etc.) which weren't experiencing any problems. It's mostly about the application these days, and not so much about the choice of hardware and/or software.


In my experience with PCS7, the redundant controller hardware is very stable and should not cause you any trouble.

The HMI level generally speaking is reliable as long as you are careful about what other software (for example: 3rd party ActiveX controls) you install that must interact with the software. If you stick to the standard Siemens stuff, you shouldn't have any problems.

PCS7 isn't a true DCS, but a PLC/SCADA integrated system, I have done several projects in PCS7 and although it has its quirks I have found the system to be both easy to configure and maintain, a lot of pre- engineering work is required to ensure a pain free project.

Engineering time is greatly reduced due to pre-engineered blocks and the Siemens S7-400 PLC platform is very robust. Profibus and Ethernet comms are easy to use and configure.

Hope this helps.


I think the man who raised the idea to upgrading PCS7 to DeltaV is not faithful or maybe he doesn't has enough KB.

I joined at least 2 PCS7 projects (worked with redundant & batching also) & until now, the system is well working.

I can help you if you need further info.


Thanx for ur replies.



By Shashank Betharia on 6 December, 2006 - 8:01 pm


Do get in touch with me at . We are one of the biggest Siemens System Integrators in
India and we are doing jobs all around the world. Check us out at

kind regards
Shashank Betharia
Director - Fox Group

By kranthi kiran on 10 December, 2006 - 5:40 pm

hi get in contact with me at
we have executed good projects in india and middle east and we also supply pcs7 engineers
for projects

get in contact
yvv kranthi kiran
project group leader
(International division)
sk automation
Mumbai, india

You can contact us for provide the service on PCS7 platform.

Dear Sir,

I think you have to be much clearer with your question. I am a PCS7 programmer and presently working for Siemens as expert for the software. First of all, the product has the trademark of a well known company, so quality and reliability is assured. You can look at the Siemens web site and you can find all the references for PCS7.

The most important thing is actually what you need, if you know what you need then you check if it is possible with the product you are purchasing. So first you tell me what is the process of your plant and what are your requirements, then we will decide whether you make the right decision or not. If you take my words then you made the right decision, you will not face limitations.

Please contact me on my email if you need more information.


By Methodologist on 1 August, 2007 - 1:09 am

Dear Minhaj,

How are you? I hope to be very fine. I worked on the Allen Bradley System at University then afterwards started my career and worked on Yokogawa's Control System Centum and PLC Stardom. During last two years we were involved in different projects, especially the Installation of the Centum CS3000R3. System configuration, Engineering, etc. What I wanna discuss is the System Topology. I don't know about PCS7. I worked on Small PLC LOGO by Siemens. We in our LAB at the Company are planning to integrate the Yokogawa with Siemens PLC and other ones.

The "functionality" of the DCS is bit different from PLCs. What I want to explore is the difference between the control functionality of DCS and PLC. I focus on PCS7, a great system by a great brand. The Parallel and Serial Scans of the Systems, I want to discuss. What do you say about it, Minhaj? Thanks.

Usman Alvi
System Engineer
Lahore Pakistan

Dear Osman,
Thank you very much for the concern, I am very fine and how about you?
Well sure we can discuse about the yokogawa DCS and siemens PCS7.

You can also contact my on my eamil.


By Reliability of SIEMENS on 31 July, 2007 - 12:51 am

Well, I fully agree with anonymous, but counterpart is he is not much aware of DCS PCS7. I don't know what a lot of problems he has faced. How was his experience? Right now I'm working on PCS7 systems and I have not ever seen such a nice and extremely powerful system. PCS7 is Process Control System but I would say it's a "Problem Cum Solutions". If you are going with H system in PCS7 then it's nice. I would like to suggest whomesoever will program for you should have good knowledge of programming in PCS 7. And he should aware of utilities present in PCS7. Your system will run life long and with no headaches.


I have mixed feelings while seeing one of my Discussion after almost 10 YEARS at

Much is changed. Life changed. I feel happy. and Satisfied what I got.

Wish you all best who were involved in discussion, i.e Minhaj

I am, now, well aware of the Difference between PLC and DCS.


Usman Alvi
Lead Engineer
Yokogawa Middle East & Africa.