Hi to everyone,

I'm new to PLC programming but someone has asked if they can control 8 UFH zones from a central location. They want to be able to see the actual temperature in each zone and be able to vary the temperature in each zone and have a setback night time e.g 23:30 to 09:00 of say 16 degrees. I have looked at the PT100 sensors, they have a distance limit of 10m. Is it possible to extend this.

Not really sure where to start, any help would be greatly appreciated.

Regards.

8 Analog inputs and 8 Analog outputs are the max of the LOGO 0BA8, so that must be possible.

For the PT100, you can make the distance longer, thats not a problem.

Use shielded cable, use 3  wire wiring tot the sensors to eleminate the wireresistance.  There is always a possibility to adjust (calibrate) the sensors in your programm. You can do it by using an Mathematical Instruction Block.

Yes.

Look in the attachment. If your PT100 always xx degrees to high (long wire?) then you can corrrect it.

In the attachment, the temp is correcting by -4. Becouse there is 1 digit (digital placement =1) it wil be - 0,4 degrees. Adjust in the mathematical instructin (B002)

Is ther any benefit in monitoring the outside temperature?

Would I be able to monitor all zones on a HMI display and adjust the individual zone temperatures and save the new values.

Any sample code would be great to give me ideas on what I need to do.

Thanks

Monitoring the outsidetemp can also with a PT100 or. a PT 1000 sensor, but the LOGO has max 8 Analog inputs, and that 8 you need for your 8 zones.

So you have to use 2 LOGO!

You can easy with VM modus send a temperature from one LOGO to another LOGO (0BA7 or 8) So you have to use only 1 outsidesensor.

On a Basic HMI screen KTP... of Siemens you can connect 7 different LOGO modules.

On the screen you can see al the temperatures, settings etc Al what you want