Platinum RTDs (Resistive Thermal Devices) are used to make very precise temperature measurements. RTDs are very accurate, and will measure temperatures up to 500 degrees Celsius. The electrical resistance of the RTD changes predictably with temperature, and RTDs are the most accurate commonly available temperature sensors.
Measuring the resistance of an RTD requires accurate components all through the system - otherwise there is no point in paying for an RTD. The resistors in the 3175 RTD Resistor Kit have a worst case error of 0.1% - translating to a typical temperature error of 0.05 Celsius. The resistors also change their resistance very little with temperature - ambient temperature variation is a significant source of error for thermocouples. RTDs with a well designed data acquisition system will not be subject to these temperature variation errors.
Wiring the resistors to your RTD allows the 1046 – PhidgetBridge to convert the resistances into a voltage, which it then measures. The PhidgetBridge is by far the most precise Phidget device for measuring voltage. The PhidgetBridge also cancels the errors resulting from USB voltage variation
Read the RTD Interface Kit product manual to get detailed instructions on how to construct and test the bridge.