S7-300 Analog input to Analog output

[dougward68]

The Value is the temperature inside the gasifier in a woodboiler. I believe it is a 4-20 input value. The thermocouple I believe has a translator unit it comes into and sends 4-20 to the PLC. I guess I need to see what the scale of the thermocouple is to determine scaling?

 

[boneless]

Hi Doug,

Yes you will have to know what 4..20 mA corresponds to. The MD112 value is a scaled value, it is a real. An analog input will be an integer.

If you want to just "copy" your analog input to your output, you can move your PIWxxx to your PQWxxx directly.

If you like, you can send me a copy of your program and I can check things for you.

 

[PLC]

Doug
Keep it simple (at this point)
What is the max of md112?
Feed those values to fc106 like jrw post shows. Then test your 4-20 output (post number12)

 

[dougward68]

boneless, I think "copying" the analog input to the output would be the easiest. I just stepped into this job. I am in a remote area of Alaska, so I can't just get people out here easily or afford-ably. That's why i am trying to do this myself. That being said, I don't have the real program with documentation, just what I downloaded from the PLC. If I sent that to you, could you decipher it?

 

[boneless]

Yes, probably. If you can describe where the sensor is connected physically and where you want the output to go out, so to say.

I will send you a PM with my email addy.