This is a BANG-BANG Controller. This trainer can be preset to two different temperatures for control action. One setting for lower temperature action which activates first really (230V AC @ 3A). The second preset for upper level temperature control actions, which activates the second, relay (12V DC). The internal 3 1/2 digit display used for displaying preset values and actual temperature. In short this instrument is: Single input, dual setting, dual output.

Specifications:
Input : J, K, RTD (PT-100)
Output : Relay(s), 230V AC @ 3A, and resistive loads
Control action : ON/OFF
Transducers : Any one of the above.
Display : 3 1/2-digit display.
Open sensor : In open sensor condition "1" is displayed.
Power : 230V AC (Mains) operated.