Choosing Siemen or AB PLC

Hello,

I am getting a new project and my customer want to use either AB or Siemen PLC, because he know that these two brands are most popular.
But he got difficulty to make a decision which one to choose.

So,he want me to make proposal and he want to know pro/con comparison between these two PLC.

Target to use latest PLC series.

Problem is that I don't have experience to prepare this kind of documentation and no idea for which key points to compare.

I am looking for help if someone already have this type of document and share with me.

Thank in advanced.

This is probably one of the longest running debates around with PLC. To be honest they are both good products, both companies build rugged PLC that can do about anything from simple logic to motion (and you are going to pay for it). Both companies have good software that works well, it is expensive and the licenses can give you hassles.
I suggest you find out what is used most by your customer or at least customers around him so they can get support or at least spare parts. If it is your choice do the same look around and pick one and try to run with it.
Me personally am an AB guy mainly because that is what is predominantly in my area of the world.

And were off... lol. I would go for Siemens, since that is "my" brand.

Where is your client located? What kind of equipment are you controlling? If its profibus/profinet I would lean towards Siemens, if it is modbus I would lean to AB. Are there more PLC's in the same installation?

Technical, I think they are pretty much the same. Overall. So it would get back to price and taste.

Who is your customers local distributor?
Which brand do they stock?
Which brand has the best support in that area?
Which of the brands is the customer more familiar with? I understand they have both on site but what do they prefer to work with, which do they find easier to understand?

If they're leaving this decision up to you, I would just pick one.
Listing the pros and cons of each device is futile, they're both good products that are capable of controlling most processes. As other have mentioned, interfacing with other equipment can sometimes make one more suitable than the other.
At the end of the day your goal is to provide a product that the customer is happy with and that they can support themselves (after installation, commissioning, and training). So with that in mind I would once again go back to the customer and ask what their preference is. More specifically you might want to talk to the people that will eventually be looking after the equipment (maintenance/support staff), I'm sure they'll tell you which brand they prefer.

A pros and cons list is hard to make unless you know everything about the customers company and can make that list applicable to their situation.

The biggest diference is probably almost always related to personal preferences.

even the costs are probably on par.

I agree with the posters so far that you should pick whichever one is most easily supported based on location. Also, what platform are the maintenance people most familiar with at the customers location. In the end, they are the ones that need to support the line, and choosing the one they like the most will make your life much easier. If they are happy then the they are more likely to take ownership of the machine and call you less for service calls. I have used both extensively, and my opinion is that AB is easier to learn and become proficient at. Siemens takes a little more time to understand for new users, and the users need to fully understand the different data types and how to use them. But, again, it depends on what the customer is most familiar with. Both platforms are very capable.

Both have good strong points. As suggested, I would look at where the equipment will be installed for local support.
AND, most important to me, is what experience does the staff have that will be maintaining the equipment. Last thing you want is to be married to this equipment after its installed because no one at the plant will take ownership.

We're all very agreeable on here today!

I'll join in as well - both are excellent PLC's, and really it comes down to what expertise there is in your area for maintenance and troubleshooting, and what your local support and stock is like. If it's hard to get spares for AB quickly, you might be better off going to Siemens.

I'm personally an AB fan, but that's because it's what I know, and the support for Siemens in my part of the world is severely lacking.

I have worked for both and with both companies, here is my perspective to add on to the already excellent points raised. I'll reiterate that neither company makes inferior products, as proven by their respective strengths in their markets despite having a cost structure that discourages the people who look for the cheapest thing they can get away with. For both to dominate like they do and command high prices, it proves that they do so by having good products and excellent support.

The major difference from my perspective is this:
With Siemens, you MUST prepare, plan and organize your project THOROUGHLY before even beginning to write any programming. The way the Siemens system works, "diving right in" gets you in trouble very fast and usually results in having to stop and start over (maybe more than once if you don't learn your lesson). Rockwell's system is a little more forgiving in that way, maybe because it started off in the US for the automotive industries where they had more electricians and technicians rather than engineers working on them in the early years. Most guys I know in this industry who have done both, have learned, from working with Siemens, to be more organized and do all the prep work, because we all know that makes any project go smoother. But for someone starting out who knows nothing about either one and gets a little ahead of themselves when they get excited about an idea or solution, Rockwell's programming environment is a little easier to back up with and modify after the fact. I can't give you exact references, it's just my experience with it (because I'm that kind of impulsive guy).

When I did Step 7 programming and jumped in, I always ended up pulling my hair out because I made mistakes that required jettisoning all my work and starting over to correct them. When I would go to my team within Siemens for help, they would jump all over me for not having thought all this stuff out before I started. I just have a hard time doing that without getting bogged down in "what-ifs" for so long that the good ideas fade into obscurity.

When I do that sort of bonehead move with RS Logix, I have always been able massage it into the project and make it work a lot easier. There are (here in North America anyway) a LOT more people with Logix experience who are willing to help out, most of them NOT Rockwell employees, who have done similar things and are willing to share, without judgement (usually) how to dig my way out of a jam.

But as the others have said, that is mostly VERY subjective to where in the world your end user is. If it was here in North America, I would say Rockwell hands down. If they are in Germany or someplace like Russia, I'd stick with Siemens. If they are in Singapore, as you are, or India or other areas of Southeast Asia, I'd say it is a toss-up. Rockwell has a VERY strong presence in Singapore now, as does Siemens.

Hi Gentlemen,

Thank you all for your posts.

My Customer in Singapore and project is for water treatment plant.

After i read through all your posts, i got some idea and knew how to approach to my customer.

Cheers...