PLC Brand Summit-AB Contrologix vs Siemens S7-400

I would like to organize a Summit to study a PLC brand standard
in our plants. I want to start this pursuit with an open mind and
many opinions from many people like yourselves in the field.
Question: If it was up to you, what brand PLC would you use in
your plants. The brands under consideration are Siemens and Allen Bradley .Please list any other brands that you fill are of good quality and price.
Question: According to Reliable Plant Magazine ,the U.S. are
going to be short 78,000 Electricians by 2014 , and the majority
of our Tech Schools teach AB PLC's.Very few have any requests for
Siemens training. I personally like Siemens ,but I need to look at the future for our company. What do you think.

Thanks In Advance

I have been on both bandwagons over the years, and from those years of experience have drawn the following conclusions:

- S5/S7 is a programmers PLC. As a standalone, doing fancy stuff Siemens cannot be beat

- A/B, especially Clgx, excels in a networked environment. Nothing can beat a Contrologix with an ENBT card, Controlnet, Devicenet, DHRIO card installed in the chassis. From one connection to the ethernet card, you can access any other device on any of the other networks

- Both companies fail at their marketing policies. I have always believed if a company purchases a certain $ level of product, software and support should be included

Ian

Where are the majority of your plants?
If in North America, I wouldn't even consider Siemens, and go 100% AB.

If spread around the world, I'd have to (very reluctantly) suggest Siemens (and make a note in my contract that I won't support Siemens PLC's).

What is the majority of your PLCs now? What are your maintenance people trained in?

Mind if I ask why your not considering Omron or Mitsubishi?

They are all located in the U.S. ,and we have some Siemens
experience with our techs,but not much. But I am concerned about
our future.A local Technical School invested about $12,000 in Siemens S7 training stations,and they have been sitting empty
for 4 years.
I did a presentation at the school ,and it was about 46
students learning AB. The instuctors said they have not had any
request for Siemens from local manufactures.

Sort of sounds like you've answered your question.
And, even if you go international, you can always use a different brand overseas. I've used many PLC's in the past, including many Siemens S7-300/S7-400's.
I've since been fortunate enough to put them far far behind. It seems that on all of those systems, the programmer owned them for life (or, until he switched companies ) since so few people could actually follow programs in them.

Add to that the fact that the AB ControlLogix platform runs absolute rings around even the 400's speed wise, I'm sticking with a total Logix based platform now.

Coachman said:

They are all located in the U.S. ,and we have some Siemens
experience with our techs,but not much. But I am concerned about
our future.A local Technical School invested about $12,000 in Siemens S7 training stations,and they have been sitting empty
for 4 years.
I did a presentation at the school ,and it was about 46
students learning AB. The instuctors said they have not had any
request for Siemens from local manufactures.

Click to expand...

I was tasked with creating some programming standards for the company I work for. We use mostly AB ControlLogix with Enet Point I/O and Panelview plus HMIs.

Last year we found a new customer that requires all Siemens components. The S7-300 DP series processors are a heck of a good deal. Our standard Siemens systems are S7-300 DP processors with ET-200S I/O and TP270 HMIs. We use WinCC Flex for the HMI programming. The Siemens products have really impressed everyone at the company, and thanks to all the great S7 threads on this site, I was able to learn what I needed to be able get through it fairly pain free. Now we have really similar systems between AB and Siemens.

Oh BTW the Siemens Sinamics motion control is really sweet.

That's odd rdrast, because in the upstate of South Carolina, Allen Bradley is being replaced with Siemens at a large automotive manufacturer.
Also several technical colleges in the area are ramping up and providing training on Step7 and the F CPU.

The organisation I work for installed two S7-400 systems about 3 years ago before I joined them. The installation and application s/w was done by a full-fledged Siemens distributor in this country to a professional standard. However after living with them for a few years, quite independently of my influence, the team determined to go back to AB. (Originally they had used PLC5's). Now we have 10 different AB CLX systems installed and more planned. We will not be looking back.

The main differences are:

1. The CLX architecture is far more flexible and scalable. The CIP comms is simply better.

2. RSLogix5000 is less resource hungry and more efficient to use. In Europe most organisations would only use degreed professional engineers to do automation, by contrast the Rockwell product is far more accessible to a wider range of users...and yet achieves the same results.

3. Rockwell's support may get some stick from some folk, but in this part of the world Seimen's support is entirely a joke by comparison.

4. We have numerous contacts in the System Integrator business who independently confirm to us that Rockwell still suits them best...and these guys get to make day to day system comparisons under pressure.

It is my reading that sometimes the American market sometimes tends to treat it's largest and most established automation supplier with less respect than it deserves due to over-familiarity. You may want to consider what might happen if there was NO native US vendor left....and Seimens was left dominating >70% of the global market.

As this forum is populated in the majority by US engineers, I tought I'd stay clear and watch for the inevitable result and so it proved.

I've nothing against AB, indeed I hope to be working with it once more very soon. My first 14 years in engineering was almost 100% AB and I loved it, when I changed company and the new company was 100% Siemens I could give a good comparison and at that time I felt the PLC3 was better than the S5 systems. The main reason for this was the connectivity with other systems, any time you wanted to link to any other system was a chore.

Over the last 10 years I have worked mainly with Step 7 and Modicon. I have done a project each with an SLC500 and a PLC5/40 and worked on a Control Logix system. With the Control Logix, I felt it had improved but I felt Step 7 had leapfrogged AB and is now the better system. The comms problems are now much improved and I feel the structuring of Siemens programs is far superior to AB and Step 7 I find more flexible to program.

Who knows though, after working with AB for a year or so, I may switch again as I do feel people put forward the system they are used to!!

PhilipW said:

In Europe most organisations would only use degreed professional engineers to do automation, by contrast the Rockwell product is far more accessible to a wider range of users...and yet achieves the same results.

Click to expand...

I don't know where you get your info from? Certainly not the case in the UK, although there are engineers with degrees whose experience is only in the software, there are still a load of us who've worked their way up from the tools.

I don't know that I'd consider BMW as an exemplar of typical North American companies

Besides which, just about any electrician with a little bit of computer knowledge can go online with an AB processor to diagnose a problem. The same people, when confronted with Step 7 will leave the line down until a technical representitive can show up.

As an OEM/Integrator, I used to use S7-315's and up, as they were a more inexpensive alternative to similar AB offerrings, but where performance, reliability, communications, networking, maintainability, and immediate support are more important than the base cost of the hardware goes, I'm decidedly against Siemens.

This is of course a personal choice, an opinion, and not authoritative on any account.

To tell the truth, I had great hopes for S7 when Siemens moved the software programming group to Princeton NJ. I thought that maybe they could take a fresh look at the software, and make it more streamlined and user-friendly than purely functional. They did fix some of the glaring bugs in Step 7, but never lived up to my hopes.

JRW said:

That's odd rdrast, because in the upstate of South Carolina, Allen Bradley is being replaced with Siemens at a large automotive manufacturer.
Also several technical colleges in the area are ramping up and providing training on Step7 and the F CPU.

Click to expand...

rdrast,
Can I get your company name so I can take it off my integration list?

Thanks for responding. It looks like a good discussion,I hope we can keep it going because I am learning alot.It is such a tough decision ,and it influences ,and sometimes upsets alot of people.

Hope you are having a good weekend.

I find there are two problems with Siemens S7:

1. It's quite different from all other PLCs. You really have to think differently (no so much as far as logic goes, but how the program is structured) to take full advantage of it.
2. Siemens stateside support is not very consistent. I know they try, but many Siemens reps just don't know their product very well.

Like anything, usually the reason people don't like something is because they don't understand it very well. They try to apply concepts from other controls literally, and it just doesn't work. For instance, I had to interface a machine to another S7 machine last year. The programmer of the other machine was new to Siemens, and he wrote the entire program in OB1 and one other function call. There was no structure whatsoever, and he had no understanding of what a data block is. And, all the while he was ranting about how bad Siemens is. This was a little extreme, but I see other cases all the time where it's obvious that the programmers just didn't understand S7 well at all. I know S7 is very workable, because I write very robust and complex code year after year with it. On the other hand, if you gave me an AB tomorrow, I would be lost. But that doesn't mean there's something wrong with AB plcs.

There are actually many big users of Siemens in the states. I know Ford is using S7 and 840D CNC controls in the expansion of one of their transmission plants, and I have a lot of other large customers all over the country (most of them being US companies, not imports).

S7Guy, I agree with you comments there, most people complain simply because Step 7 is not an AB and start listing things it does not do to emulate an AB (for users of other PLC's replace AB with theirs).

It is different, its a different concept, some of the things it does is a lot better than AB, for other things AB is a lot better.

I suppose the crux is people are happier with what they know and perhaps when quoting for a job don't allow for the extra time of getting to know a new processor, get into trouble and then its all too easy to blame the processor.

Most integrators don't bother with training courses, I know here in the UK this is definately the case.

I recently worked with one company where their engineers didn't even know that standard libraries existed, never used UDT's as they didn't understand them and banned STL (I know people have said that this is the case in NZ and US as well), which is like boxing with one hand tied behind your back.

In one post someone says any basic electrician can pick up AB but not Siemens, I totally dispute that statement, yes electricians do struggle with the concept of STL at times but in the end it exposure to the system that is required.