When two wires composed of dissimilar metals are joined at both ends and one of the ends is heated, there is a continuos current which flows in the "Thermoelectric" circuit: Thomas Seebeck made this discovery in 1821. Now if this circuit is broken on one end, then the net open circuit voltage is a function of the junction temperature and the composition of the two metals. All dissimilar metals will exhibit this effect.

The AAS Temperature Control System uses such a Thermocouple to sense the temperature in the return-line side of your filter and a 7018 Module within the DP7000 Distribution Panel converts the thermocouple data to an RS485 serial I/O data signal to be sent back to your PC for display on the AMACS Software Program.