Small PLC With Display?

Hi all,
I am looking to replace an old set of trip amps that used a complex thermocouple setup that did averaging electrically. I will run back all the 8 thermocouples to the panel and average in the controller so we know the state of each device. Trouble is there is little space and I need a display to replace the old analogue gauge and to show the device faults etc. Is there any controller that can handle TC inputs, three digital outputs and has a rudimentary display to show the 8 temperatures?

I know how I would do it with a basic CompactLogix CPU, 2x IY4, OW4 and a 2711R-T4T but the customer is looking for a dirt cheap solution!

Any thoughts, I only use Rockwell so don't know the market for lower end controllers, haven't even used a MicroLogix yet.

PS. This is in a 1970s relay logic panel.

Siemens Logo used to allow this, perhaps that's an option? Not sure on the TC inputs though...

i doubt there are many all in one controllers that can handle 8 tc inputs. you may look at idec, they have an all in one, but you may have to use an external tc to modbus device and pull the info in like that.



my preference would be to use a click and cheap touchscreen from automation direct.

You are looking for plc hmi all in one, you can try:

https://www.maplesystems.com/hmi-plc-combo/
https://www.unitronicsplc.com/
https://www.ezautomation.net/HMI-PLC-All-in-One/eztouchplc-family.php

Look into the Horner OCS product line.
https://hornerautomation.com/product-category/all-in-one-controllers/xl-series/

Another question may be how accurate and repeatable do you want the TC signals?
Specifications have become a little more tight over the years.

Thanks all, I'll have a look into those suggestions.

NetNathan said:

Another question may be how accurate and repeatable do you want the TC signals?
Specifications have become a little more tight over the years.

Click to expand...

As long as they are within 2 degree C @ 500 DegC that will be fine, its very basic here.

cardosocea said:

Siemens Logo used to allow this, perhaps that's an option? Not sure on the TC inputs though...

Click to expand...

There is an 8-channel RTD module for Logo. But it is for Pt100/Pt1000, not thermocouples. So I think it is a dead end.

I suggest to use a Siemens S7-1200 (delivery status 1-2 months) with the 8 channel TC module 6ES7231-5QF32-0XB0 (delivery status 3 months). And for the HMI a KTP400 basic panel (delivery status 1-2 months).
Not as dirt cheap as a Logo, but much less expensive than a compactlogix.

maybe its not what you're looking for but you could use something like this just to display the temp and some control
https://www.fujielectric.com/products/instruments/products/controller/PXE.html

Rockwell solution would be:
Micro820
2080-REMLCD Remote LCD option
2x 2085-IRT4 for thermocouple input

PR electronics have a signal calculator there can calculate average from TC measurement.
They also have a display you can put on the output of the calculator.

https://www.prelectronics.com/products/multifunctional-devices/5100/signal-calculator-5115a/

Not sure whether you have found a solution to this, but you could do it with Weintek IO and HMI using CODESYS.
2 x iR-AI04-TR
1 x MT8051iP
Total cost about £450 - £500!!