[SOLVED] easy 512 DC-RC temperature measurement

Hello.
I just started learning about PLCs. My primary field of expertise is acctually electronics and microcontrollers, but for a sake of my employment, I have to learn to work with PLCs. I already know basics and I know how to write ladder diagram. I also finished one project in work with easy 822 PLC from Eaton.
Some time ago, my friend gave me this controller (easy 512 DC-RC). I didn't know, what to do with it and now I came to idea, to control radiators in one room with electric actuators. The problem is, that I don't know if this controller can measure temperature and then work with this data. It has 1 analog input, that could be used for some analog temperature sensor, but it only has analog comparator, so this kind of regulation would be "quazy" regulation. It is possible to measure voltage or current with this controller or is it just possible to compare two values?
I am asking you guys, because Eaton has very poor support with this controllers. I don't want to throw it away, so I have to use it somehow.
Thank you for all of your answers.

Does it have an onboard temp sensor? Or else obtain a sensor whose resistance changes with temperature. Make it output a variable voltage with a schematic like those below.



These are simple circuits. You'll need to do a lot of adjusting (programming?).

How long will wires need to be? Long wire runs tend to pick up ambient noise and mains hum. Therefore long wires ought to carry on/off signals, if possible.

I would also like to display temperature on build in display, but that would be inpossible, since this controller doesn't have aritmethic operations. That's why I asked, if it's even possible to measure temperature with this controller.

bmandl said:

It has 1 analog input, that could be used for some analog temperature sensor, but it only has analog comparator, so this kind of regulation would be "quazy" regulation. It is possible to measure voltage or current with this controller or is it just possible to compare two values?

Click to expand...

You said your PLC can not do arithmetic operations, so you will have to use Voltage instead of Temperature values.

Analog input reads a voltage given by a temperature sensor, convert it with the A/Dc and store it within a mark (memory) than, use the comparator to compare with the desired voltage (this voltage means the setpoint temperature or temperature you want to reach).

Yes, this is the approach I've been thinking at first. It's not verry favorable, since I can't display actual temperature. I just thought, that someone know this controller and could confirm that measuring analog values is not possible. Thank for your answers.