Low-Voltage Data Acquisition

Data acquisition and control systems need to get real-world signals into the computer. These signals come from a diverse range of instruments and sensors, and each type of signal needs special consideration.

Thermocouples provide a low-voltage signal, typically a few millivolts. The relationship between temperature and voltage is non-linear. The voltage depends on: Temperature measurement systems using thermocouples need to provide a means of measuring the cold junction temperature (often using a platinum resistance device) and an algorithm for linearising the voltage readings to temperature. Microlink hardware runs the Interface Management Language (IML) whose linearisation functions currently support B, E, J, K, N, R, S and T type thermocouples.
 * 1) The temperature difference between the thermocouple junction itself and the point where the thermocouple wires terminate - the cold junction.
 * 2) The temperature of the cold junction.