Because the problem is not in the code anymore.

Measure the voltage across the resistor and check what temperature it reflects.

It may not matter, but if the unused PLC input is a voltage input (AI 1 on -X11 terminal 3), it should be jumpered to -X11 terminal 1.  If it is current input, no jumper.

If you have a HF or HS s7-1500 AI module where the AI's are not multiplexed, it should not matter.

Are you certain of the -50..150C range?  Is the TC used the proper type for TA2415 to get that range?  I see too many times where Type-J and Type-K TCs get connected incorrectly - especially when there are both J and K type TC jacks available and close to each other.

Erik_B&M

Hello Dchartier,

Thank you for your support. But problem is not solved.

I have change the settings by norm_x to 5530. but i have a big temperature differents. 
In the attachments more info.

I hope you or some body else can help me.

The specifications for the IFM device is given
[LINK: https://www.ifm.com/us/en/product/TA2415?tab=details]

From that the following extract:

A 500ohm resistor is used to get a 10V signal, but..

1. The instrument cannot drive the load (see above picture).
   
   
2. The input impedance of the PLC is not infinity. The input impedance PLC influences the effective resistance for the current. You will be surprised of how much -- especially for the onboard (10 bit) analog inputs on the PLC.

As Mr. Jacek suggested - measure the voltage over the 500ohms and see if that relates to what the PLC gives. My opinions means nothing if the analog on the PLC does not correspond with the hand-meter's voltage measurement.

Then there are some choices: 

1. Calibrate the PLC input to what the actual temperature measurement is. Because the maximum 300ohm load specification is less than 500ohm, expect non-linear behaviour.
   
   
2. Use an analog 4-20mA card on the PLC. [recommended]
   
   
3. Use a proper analog signal converter.
   
   
4. Use another IFM device.