Hardware/SDK recommendation request for small project

Hello, thanks in advance for any advice on this topic.

I have a contract to develop a control system for a piece of industrial equipment. The project is not extremely complex - my first pass at the design indicates a state machine of perhaps 8 steps, about ten inputs and four or five outputs. Control of a stepper motor is part of the picture as well.

I have quite a bit of experience designing in VHDL on complex gate arrays, and have some practice also with programming PLCs using IEC 61131 tools. But that was my last job, and now I am independent and the project budget is pretty tight.

I've found some a low cost PLC from tri-plc.com and the total cost including software is less than $500 which is great), but upon close inspection the development software looks a bit weak. It does support some high level coding but I'm a bit concerned about things like only allowing a single letter as a variable name.

Have I missed some vendors that might have a combination of hardware and SDK with some high level capabilties at a low price?

thanks!

What is your customer's preference??

Cheaper is NOT always best!! As a matter of fact, cheapest is rarely best.

I would much rather pay a little (even a lot!) extra to have something I can support myself, rather than have some obscure, albeit cheap, system that nobody has ever heard of and can't get reasonable, local support for.

You truly do get what you pay for -- I'm battling a system right now at one of our international facilities where the original controls-guy went the cheap route. Had a part fail that we can't identify that, therefore, we can't get support on. Yup, it was the cheapest... and the first to fail and the hardest item in the system to source. Plus, now, we're going to have to travel internationally to install and reconfigure the system for a $400 part.

An 8-state, 10-in, 5-out system can be done by ANY of your entry-level PLCs (AB, Siemens, Schneider, Automation Direct, ....) and you'll be giving your customer something that they will be able to support for a much longer time than the cheapest system you can buy.

If you want something based on 61131, then look at systems based the Codesys (www.3s-software.com) software such as Wago or Beckhoff.

I tend to favor Beckhoff for many reasons, a couple being that you can get a complete PLC for around $500, then download the TwinCAT programming software from their web site for free. It says it is a 30 days demo, but that is only for the PC based runtime. The programming environment does not expire.

But you should first check to see if your customer has any requiements or restrictions on PLC brands and models.

Friendlyfire,

We offer a free programming package for our controllers. Our package is strictly ladder based.

You read about our software and download a copy at the following url:

www.entertron.com/software.htm

The download is free but password protected. You will have to register by completing the following form:

www.entertron.com/form.htm

Based on your I/O requirements, Any one of our controllers will satisfy your requirements. As to which is the best solution, we would need to know more about your application. An overview can be found at the following url:

www.entertron.com/controllers.htm

If you have any questions, feel free to contact us. Our contact information is on our web site.

Hope this helps.

God Bless,

Hi, thanks for all your prompt replies. I will follow up your suggestions. OZEE, I agree, cheap is not always best, but this is project is in support of a garage based enterprise and the budget does not allow $1K or more for a PLC and another couple of grand for a programming package. Steven, I'll look into your products but
I really prefer not to design in ladder logic if I can help it. Can I transfer code from another tool onto your PLC? Archie, your advice sounds promising and I'll look into ASAP!

FF

Archie, I have reviewed the Beckhoff web site in detail and it appears the company is exclusively focused on PC based controllers and not stand alone PLCs. Am I missing something? When you said a PLC for $500 did you mean a low cost PC with the appropriate software? If you don't mind, I could use a link to the PLC you had in mind.

The CodeSys platform looks excellent, exactly the sort of thing I am looking for.

I discovered a product that looks very interesting - RabbitFlex. At first glance this product line seems to offer the combination of price and decent programming environment I am looking for. I'll search this forum for any mention of it...
FF

On the Beckhoff site, go to Fieldbus componentents .. Bus Terminal .. Bus Terminal Controller .. BCxxx, BXxxx.
I particularly like the BC8150 which has ethernet onboard at only approx 250 USD. (no I havent actually used it, only noticed it on the website).
You then have to add KLxxx i/o terminals to suit your requirements.

Beckhoff puts heavy focus on PC based control, but their BC and BX line are stand alone controllers based on a proprietary operating system. The CX line are stand alone controllers based on either WinCE or WinXP embedded, but start at around $800.

If you wanted to get a feel of the software, you can download TwinCAT and use it as a PC based controller. The software is the same for all of their platforms. Here is a link to a brief intoduction to TwinCAT:

http://www.youtube.com/watch?v=h54gtseymrI

FF,

The simple and quick answer is no, you cannot utilize other tools in conjunction with our software.

Sorry.