Platinum RTD Sensor - PT100

A PT100 is a Platinum RTD (Resistance Temperature Detector) with a resistance of 100Ω at 0°C which changes with temperature. It is suitable for applications in the temperature range of -200°C to 600°C but are more commonly used in the range -50°C to +250°C.To use this sensor with our Qwiic PT100 ADC please connect the red wires to terminals 3 & 4. Connect the white wire to terminal 2. Short the A and B pads on the back of the Qwiic PT100 PCB. Be sure to use Example4-3-Wire from within the ADS122C04 library.How do PT100 sensors work? On four-wire sensors the red wires are connected to one end of the resistor; the white wires are connected to the other end. For three-wire they use the same scheme: the two reds to one end; and one white to the other. Using a DMM you should see ~1 Ohm between the red wires; and ~100 Ohms between red and white.