A very simple PLC application & zero budget for hardware ??

[robinbreak]

This is a story of rubbing two nickels to make a dime.

I've been assigned to make a simple PLC application:
INPUTS: two temperature sensors (thermocouples)
OUTPUT: 4-20mA to drive a VFD (that operates a cooling fan)

Existing equipment:
Cooling fan + ABB VFD (already tested), and a PanelView Plus with a broken screen (that I can get repaired for $300).

I'm looking for a cheap way to build the hardware/software here.

ROUTE #1: Rockwell
- buy a cheap Rockwell PLC (even used), like a CompactLogix (suggestions here are appreciated), with the necessary cards (thermocouple and analog output)
- buy the software license
- repair the HMI (hopefully is compatible with CompactLogix)
I will probably spend $2000 here

ROUTE #2: third parties (here is where I need your comments)
- trying to find on the market a cheap PLC + HMI (touchscreen) + software bundle that will get me running
- I've started to look at Schweitzer for the package which seems fairly cheap
- Any other third-party options?

Thanks to everybody that will take the time to contribute

P.S. the budget is not really zero, but is quite limited

 

[xnuke]

Check out AutomationDirect components (I am not affiliated). They have options that are less expensive.

xnuke
"Live and act within the limit of your knowledge and keep expanding it to the limit of your life." Ayn Rand, Atlas Shrugged.
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[LionelHutz]

Yes, automationdirect.com. Forget A-B stuff if you want to be cheap.

 

[RedSnake]

To get this I guess isn't possible for you, but I got this in the mail the other day, I haven't checked into it so I don't know if there is any licenses costs.
It happens from time to time we get these offers for these, one in all small PLC:s like this one even from very well known manufacturers but then there is usually licenses costs involved.
What you can find in US or Canada I don't know.

Try our PLC with 4.3" screen
SM43-J-T20-H
SAMBA OPLC 4.3" color touchscreen
Feed 24VDC, 10 digital inputs 2 analog/digital inputs, 8 transistor outputs, USB port for programming.
Now at a special price of SEK 3,400
Stock item Applies to 231031

The all-in-one software:
Develop PLC, HMI, VFD and Servo applications in a programming environment
Configure hardware and communications
Establish modem and data communication
Test and debug your programs
Software Utilities Suite: tools for remote access and data management
Control your application remotely from anywhere and anytime from the app from Google play or App store

3,400 SEK is around 314 USD.

NAFO Sergeant Anna Gr 69th Sniffing Brigade

 

[eeprom]

This reply might be too late, but Compact Logix is NOT cheap. Stay away from that if you are trying to save money. The panelview is going to force you to stay with AB. The problem with AB is that they will kill you on the software, even for obsolete controllers.

1. The AB Micro800 series is reasonably priced. They are about 1/6th the cost of Compact Logix. They are the only AB controller that offers free software.

2. You could also find a used micrologix 1100 and the required cards on ebay. You will have to buy the software.

3. Automation direct (as has been mentioned earlier), but then you will have screen compatibility issues

4. Use a raspberry pi and a nextion screen. This isn't a PLC, but you could do this project for about $200 in parts. That includes a CPU, screen, temperature probe (serial), a relay output card, and an analog output card.

 

[jraef]

You could get a A-B Micro820 with a 2 channel thermocouple input and an analog output module with a small remote mounted LCD screen and cable for $933 LIST... both are programmable with Connected Components Workbench software, which is free.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[thebard3]

When tasked with delivering a system to perform some function, I determine the needed specifications, select the equipment (soft and hard) and forward to management. It's their decision whether or not it's important enough for the investment needed.
Yes, ControlLogix controllers aren't cheap. I have never seen one fail.
Micro800 and Automation Direct stuff is a different story.

If you buy a used ControlLogix controller like you suggest, you better check compatibility with the controller, firmware versions and connected equipment because you can't just willy-nilly start connecting stuff up like that anymore.
L3x compact and L6 processors are mostly unsupported now so if you buy anything like that you'll pretty much be on your own.

Brad Waybright

The more you know, the more you know you don't know.

 

[seanleed]

We use Siemens LOGO controllers for relativel simple setups like that for the apprentices to play about with.
You can get a LOGObox that will have a controller, PSU, small HMI and sofware as an all in one package.

We get ours from RS in the UK, but they are also available everywhere else in the world:

https://us.rs-online.com/view/search?keyword=logo