Choosing the right PLC

Good day all.


I work for a small company that would like to start automating the production of our goods. I have been tasked with doing some research and finding a suitable option for a PLC to use. As far as providers go, I have done a bit of research into products offered by Rockwell Automation, Schneider Electrics, Siemens, Mitsubishi and Omron.


I was wondering what people's opinions of these various companies are, or if there are any others people would recommend. We don't need anything too large, to begin with it will only be managing a handful of things, but some room to grow would be good.



Ideally cheaper options are preferrable but it doesn't have to be anything too bargain basement.



Finally from the programming side, higher level languages are appreciated. I come from a programming background and am quite familiar with C and the like, though I've done some practice on ladder logic in a simulator and found it quite understandable.


As this is the first one we have no ties to anything specific and can go any which way, but I would like to make sure we get something that's a good match for the job from the get go, hence why I have come to consult with people in the know.


-Richard

So this will be a one-off plc that may expand in functionality.


Are you going to be the sole programmer - will maintenance personnel be expected to get involved with the program when there is a problem?


What about HMI - buttons/lamps or Touch panel or nothing?

As a new user the brand you pick is less important than the quality of local support. My advice is to call in the local suppliers of the different brands and have them pitch their products to you. Make sure you are talking to the local person who will be supporting your efforts, the one you'll be calling when you have questions. Pick the one you feel most comfortable with.

Steve Bailey,
+1
james

I would develop a relationship with a local systems integrator. You will pay more but you will be buying experience, reliability and emergency response. I recognize this is not the best way for everyone but I'd look at it and maybe even talk with some integrator's and see if it makes sense for your needs.

I personally include in my decision making process the software that I will work with. For example anything Omron that requires the use of CX Programmer to me is a no no, same for rockwell RS Logix 500. Workbench Components (is that what it is called?) seemed promising when I tried it a couple of years ago and it probably got better since.
RSLogix 5000, Siemens TIA, Beckhoff Twincat3, Schneider Unity Pro(haven't used it for three years), CodeSys, sure, I can work with any of them and go through the learning curve.

I would look at Siemens and Mitsubishi, they both have strong support in the UK, I cut my teeth on Siemens and was an approved engineer for them so in some sense it is what I would recommend, however, I have worked extensively in all platforms and do not recommend AB as the techconnect & all equipment is expensive, seems to have major issues every time they update the versions and compatibility with existing equipment.
I now prefer Mitsubishi, reasonably priced and easy to use, the down side are chinenglish manuals. They have a good spread of PLC hardware from small bricks to motion PLC's Getting one of the reps on-board can pay dividends and possibly some discounted software. You will get a lot of recommendations on here and a lot will be for Rockwell (AB) well I think most members are from the states but support from RW is well out of reach for small companies once you get into the larger hardware. I do not discount Omron but personally I do not like it as much as Siemens & Mitsubishi, I suggest you stick with the well known ones, yes you can get cheap systems but like anything you get what you pay for and the long standing systems have proved they are here to stay.

As others have stated, the local support is usually key if you are going to be in the same location all of the time.

If someone other than yourself, such as a maintenance person will be involved in troubleshooting/etc, I highly recommend using ladder and not C or some other programming language.

Before deciding what manufacturer's product you wish to use, answer some other questions first.
1 - What do you want it to do now? in six months? in 5 years?Does/Will it need to interface with any other equipment?(Data transfer etc)Types of I/O modules needed?
2 - Who is going to program it? Cost of software? Is tech support from the manufacturer or an integrator readily available? At what cost?
Once you have these answers, now it's time to go shopping. Talk not just to suppliers but end users. Do you have customers/suppliers/ associates that use PLCs in their processes? What ones? What results?
I mean, if you just want cheap, I have an old SLC150 "brick" that you can have for a low, low price.

My impression:
-Mitsubishi iQr and iQf, best overall experience. 36 month guarantee.
- Siemens S7-1200 and S7-1500 are quite ok, but for me Mitsubishi gives you much, much more for same price.
- AB support in my part of world is bad.
- Schneider has very competitive price and it is Codesys,
- Unitronics is ok for small projects.
- Fatek is outdated, but cheap. Software is terrific.
- Wago is OK, but support is bad on my part of the world.

Thanks, that's excellent feedback.

I haven't worked with mitsubishi past GX developer. I just had a very quick look at the two CPUs you mentioned and their engineering software and I am very likely to look into them more. They look very promising.

Based on your list I would go either Mitsubishi or Schneider.

Have you looked at Beckhoff?

parky said:

I now prefer Mitsubishi, reasonably priced and easy to use, the down side are chinenglish manuals.

Click to expand...

You actually read the manuals?

Steve Bailey said:

As a new user the brand you pick is less important than the quality of local support. My advice is to call in the local suppliers of the different brands and have them pitch their products to you. Make sure you are talking to the local person who will be supporting your efforts, the one you'll be calling when you have questions. Pick the one you feel most comfortable with.

Click to expand...

To add onto this, if I were looking into which brand to use, I would see if the local distributors had demo units that I could poke around with, or even if they wanted to drop by my office and show me some of the features (might be a bit difficult these days).

If you are not a part owner of this company then do them a favor and avoid the high level languages. Mainly so that the next person will be able to easily pickup where you left off. KISS is the best train of thought. Just because you can make some cool code to save a hundred rungs doesn't mean you should. I don't even like using AOIs (Add On Instructions) unless they are very simple.


As far as PLC type I agree with the others above. Develop a relationship with the local distributor or SI. Product Support is a BIG deal these days. If a part goes bad at 6PM Friday night you want someone who can get you one in a couple of hours, so make sure they stock the parts you may need.


Avoid special order equipment for critical production. If you can't then budget to keep spares of those. If you going to have to get one, get two.