Digital controller for refrigeration

ATR131 is a digital controller size 32x74mm for refrigeration technology. Two versions are available: with single relay for compressor (with timed defrost) or with 3 relays for the management of compressor, defrost and evaporator fan. Temperature control is ON/OFF with hysteresis. Compressor stops at reaching of setpoint and restarts when temperature exceeds setpoint plus hysteresis. The version with 3 relays includes 2 defrost modes: electrical (compressor stops) or hot gas (compressor keeps working). Other programmable functions: defrost frequency, time counting mode, temperature at defrost end, max. duration. Sensor on evaporator and relay of fan are used to control defrost cycle: it is possible to set temperature for fan switch-off, delay at switch-on after defrost, combined operating of fan and compressor. High and low temperature alarms can be excluded for a programmable time, after defrost or at switch-on of the device. Different operatings are selectable to protect compressor against short cycle. RS485 with Modbus RTU / Slave protocol available as option. Memory Card for quick configuration