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Need a cheap PLC for a low end application
Require a cheap PLC with approx 20 DIO and 8 AI signals.

Can some one please suggest a cheap PLC with approx 20 DIO lines (12 O/P + 8 I/P), AC/DC operation, 8 Analog I/P and RS232 communication?
Scan Frequency can be low to medium. Need to put together my own ATE.
Thanks for your help.

By William Sturm on 15 July, 2009 - 4:09 pm

Bill Sturm
Abbeytronics LLC

By sushant chanana on 15 July, 2009 - 10:55 pm


Go to ,there you will find pls and I/O modules. PLC approx 200 USD and I/O modules around 100 USD

You can also go for Rockwell's low ended PLC's which may fulfill your requirement.

Sushant Chanana

Cheap and best controller, hmi, too. are available at

I would suggest a Phoenix Contact ILC. Look at the ILC on:

By Dweebyone on 16 July, 2009 - 11:45 am

Try Schneider Electric Twido PLC. You could go for a 24 I/O (digital) base Twido. Then add-on analogue modules. Coms is RS485 by default, but you can add a Rs232 port. ASCII/Modbus RTU.
S/w is a free download. Low cost hardware, simple s/w.

See link, then selct downloads.

By Curt Wuollet on 16 July, 2009 - 7:20 pm

No doubt you will get a lot of opinions. The cheap PLC is going to be the one you have software for. Or the ones with free software. Automation Direct is cheap. Their new PLC with free software doesn't offer analog yet when last I looked. The software for some PLCs is many times the cost of the rest of the project. The digital stuff is not an issue, but analog is another region where some vendors get really spendy. So I would be looking for the most reasonable software and analog and let the digital stuff be a given.

Cheap is not often mentioned in the same sentence as PLC, but, it's getting better all the time as vendors in the crowded market run out of BS to compete on and have to sell value. I never thought they would run low on BS.