I have a new T3-886 and setup to read a few 0-5VDC inputs, a 4-20ma flowmeter and your clip on temperature sensor 10k type 3. Whenever the flowmeter is flowing above about 15ma the temp sensor reading goes down by alot. If I am reading normally 73F, it goes down to 20F and -20F only when the analog input is above about 15ma and above. I tried using different inputs and the same thing happens. I cant use these temperature sensors if this is not fixable as the PLC is controlling temp and flow at same time.
Any time there’s an interaction between one sensor, or output for that matter, and another of the inputs, that points to some sort of grounding issue. Current from one area is flowing to another causing slight voltage shifts resulting in temperature swings.
If you are using one of the analog outputs on the T3 device to generate the power supply for the 20ma flow meter, that helps actually, becuase we know all sensors are sharing a solid ground. If you are using a separate supply for the 20ma transducer then you need to spend time making sure the GND of all devices is well connected to earth. Current from one supply should not find its way into the other devices through the transducers, outputs or inputs of the system.
Send a wiring diagram and I can make some better suggestions. Make sure to include all power supplies and devices, paying special attention to the grounding of the system.