Newish PLC user - need to choose a brand

[cfduarte]

Hi all,

We are a small company involved in water and wastewater treatment and have been feeling the need to "upgrade" our standard electrical panels to more modern ones integrating a PLC (easier to modify, cut down on relay cascades and allow for analogue signal processing).

We will be subcontracting all electrical work outside the company (we have no in-house electricians) but want to program the PLCs ourselves.

I have a little experience with PLC programming (see below) and a Chem Eng background, so ideally I would go for ST over FBD (second option) or Ladder (only if really needed).

In termos of experience, I worked (as end-user / small modifications) with AB Micrologix and FactoryTalk (hated it), B+R (in Basic, no major problems) and now with some Siemens LOGO! modules (FBD - ok, but limited).

We are talking about very small projects, so cost is an issue, especially software cost, as the payback will be invariably long. Also, in Portugal, we are a bit restricted on availability of modules (with Siemens, Schneider and Omron at a distant third rulling the roost).

I have been looking at Beckhoff and Siemens (S7-1200), but each have their problems: Beckhoff panels are VERY expensive and Siemens require paying for software and the whole "number-based" vs "tag-based" structure sounds confusing for larger projects.

For a "basic" project (small display, small PLC with up to 8 DI/DO and 4 AI/AO, Ethernet-based comm) I wouldn't expect to pay more than 500-750 euros for a full system.

I would really appreciate your input on options, alternatives and suggestions. Thanks!

 

[Saffa]

I don't do a lot of PLC work at this sort of level, but the two PLCs I've used that would fit in this range would be:

Unitronics (the basic models with the 2 line LCD display would fit your budget, the more fancy Vision ones probably not). Software is free. The basic ones don't have onboard ethernet though. Ladder only from what i remember.

The new Schneider M221. Software is free for this model. FBD and ladder only. Has an optional basic display. My price is less than NZ$450 for the basic brick, two onboard analogs but adding more may push you over budget.

Others may know some cheaper ones but 500 euros for analogs, ethernet comms and an HMI may be a bit of an ask!

 

[cfduarte]

Thanks for your input.

Let me clarify some things (my initial post is unclear, sorry):

- My "budget range" is 500-750 Euros. 750 would be for a system with a touchscheen HMI and 500 for a HMI-less system. The HMI doesn't need to be overly large (close to 4 in would be ok) or colour. The eternet is for convenience, as I would like to avoid carrying proprietary cables around for programming.

- I am trying to find something with ST or similar for the main programming. I had an awful experience with Ladder on an AB sytem - it's good for on-site debugging, but an absolute pain for ground-up programming for someone with a Chem Eng background (which, in my case, was mainly FORTRAN-based) - and I deal reasonably with FBD, but find it limited and cumbersome for some things.

 

[KalleOlsen]

Hi!
This one from Horner is a HMI/PLC/IO combination.
I only found prices in Norwegian Kroner. If you divide by 8.5 you approximately get Euros (and I bet the list prices in Norway are among the highest).

I have never used Horner, but seen it once; in labour by a customer.

http://kotek.mamutweb.com/Shop/List/XLt/243/1

Kalle

 

[sixstringz]

I am using the Micro800's for stand alone projects, free software (ST,LL and FB programming).

http://ab.rockwellautomation.com/programmable-controllers/micro800

 

[jethridge]

Have you checked out Automation Direct? Their software is free and their PLC's pack a punch for the price.

Advanced HMI is a free HMI software and there is a user on here with the username "Archie" who is a guru with it. He'd be able to set you straight with it. Delta HMI's are fairly inexpensive and I think their software is free also.

 

[gclshortt]

I agree with jethridge. The Do-more PLC from automation direct would be a good fit. The free software and simulator are hard to beat.

http://www.automationdirect.com/adc/Shopping/Catalog/Programmable_Controllers/Do-more_Series_PLCs_(Micro_Modular_-a-_Stackable)

The simulator will also handle the Modbus TCP protocol directly, so you can test your communications before investing in any product. Here is a link to the software.

http://support.automationdirect.com/products/domore.html

Regards,
Garry
http://www.accautomation.ca

 

[JaxGTO]

I have been an Allen-Bradley guy for 30+ years. With that said and the lack of quality of AB these days, I would look at PLC Direct. It's way cheaper, proven in the field and probably more reliable.