Real-Time Measurement and Control

Using NI 9226(D-SUB) to measure the resistance of RTD PT1000 temperature sensors

I have been trying to measure the resistance value of RTD PT1000 temperature sensors using FPGA I/O Nodes and I am getting wrong values.

A little background: We have an FPGA Program for a Dialysis machine prototype using CompactRIO 9039 Chassis that has been used without problems for one year now and my task is to use that program for my current Testbench, the testbench has the same components as the prototype and is built in the same way, just a little bit more flexible. The only difference is that we are using CompactRIO 9049 for this testbench and NI 9226 (D-SUB) while the other prototype is using NI 9226 Spring terminal.

Here is my approach and tries so far: 1) I measured the resistance at the Pin connector and got 1000Ohm ( what I expected)
2) I used a DAQmx Program and got the expected value
3) I used the NI Max Testpanel and got the expected value
4) I checked my soldering of the wires to the Pin connector and made sure that everything is right according to that tutorial :https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019MQSSA2&l=de-DE

5) Tried another NI 9226 (D-SUB), still got the wrong values with the FPGA Modul and tried other temperature sensors

6) Made sure that there is nothing wrong with the FPGA Program.

I am using a simple program to read the values of the resistance and I attached pictures of the frontpanel and the block diagram. TSE is the temperature sensor I am measuring the resistance from, TSBIC and TSD are not connected, TSRES is just the value Im getting from a resistor I connected to the positive and negative pins and connected a jumper between COM and the negative pin just to see if I could the right value of the resistance by chance.

My question: Is there anything else I haven't tried that might be causing the problem? I even called the NI Customerservice but couldn't a helpful solution from them. I would be so glad if someone could lead me to the right direction as I am pretty clueless at the moment.