Hi John,
Most thermocouples are 2-wire. A 4-wire thermocouple is basically two 2-wire thermocouples with the metals joined together. The thermocouple is self exciting, so you measure a voltage created by the thermocouple. You need to make a correction based on the connection to the PCB in an area called the isothermal block. This is a thermally isolated area where the connections of the thermocouple to the PCB are all at the same temperature. The temperature must be measured and a correction factor added to the voltage measurement based on the cold junction of block (cold junction compensation).
I cannot tell exactly how to connect the sensor. I assume that there are two different color wires. I'm guessing that you would need to determine which direction of measurement is positive and then connect the wires in an alternating fashion. AIN0 and AIN2 would have the same color, and AIN1 and AIN3 would have the same color. This connection would only be a guess on my part. I have never seen a 4-wire thermocouple. I have only read about them.
Best regards,
Bob B
