PT100 on a TM3TI4

[Wouter94]

I have a couple of 3 wire PT100 sensors that are connected to the TM3TI4 module. This module is coupled with a TM221CE16R. I have noticed that is need to program offsets in the program for my temperatures because the measured temperature is not equal to the actual temperature. I see that the value changes depending on how long the cable that the PT100 is connected to is. but as far as i understand, the cable resitance shouldn't be a problem with a 3 wire PT100 because the cable resistance is being calculated and the input should account for that. Is there somewhere in the program that i need to activate this or is my problem somewhere in my cableing?

[Bastian_Schmitz]

Hi,

If you use a 3 wire sensor you need to connect them like described here or show in this video

You did not adjust a value regarding to the cable lenght.

If you have still a difference you need to adjust the value with an offset in your program.

In my personal opinion PT100 is not the best probe regarding accuracy. It is very good regarding stability and reolicability.