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Controller Catalogue_2015 04/08/2015 13:43 Page 28 Refrigeration Head Pressure Controller The Head Pressure Controller (HPC) varies the speed of EC fans to control the head pressure of a refrigeration circuit. The pressure sensor input and speed control output to the EC fans are 0-10VDC, control of 24 fans maximum. The set point may be set locally by means of a trim device on the control PCB. An optional PC interface allows set-point configuration and data logging from a PC. The controller allows the refrigeration system to be operated with a Floating Head Pressure, which can provide substantial energy saving and reduced compressor workload leading to 230 50 °C mm mm mm 180 93 58 -35...+60 IP Rating CN1089 Height Hz Width VAC Length Frenquency Part Number Ambient Temperature Supply Voltage increased service life. 66 • 0-10V Pressure Sensor input • Pressure Set-point set by on board Potentiometer or from PC interface • Microcontroller uses PID program with configurable P, I and D gains for optimum combination of response speed and stability • Two 0-10V Fan Speed Control outputs (Open Collector output option by DIP switch setting). • Control of 1-24 EC Fans per controller, maximum 12 EC Fans per 0-10V output. • Fan speed offset option for the two 0-10V outputs provides Ultra Low Volume control for maximum energy saving at low ambient temperatures. • The controller also optionally monitors Condenser and Ambient Temperatures (using two thermistors) to provide optimised energy use at high ambient temperatures. • For small systems (1-2 fan systems 230VAC, 13A maximum fan load) the fans may be powered via controller PCB. This avoids the need for any additional connector blocks, wiring and associated enclosure. • For Tachometer Output fans on small systems, 1-2 fans, the controller can monitor Fan Tachometer signals. For other systems, 1-24 Fans, the controller can monitor Relay Alarm type fans. • Controller relay alarm output, contacts rated 60VDC, 100mA, Fan or Thermistor Alarm. • Optional PC Interface for Configuration and Data Logging. • Parameters may be set from PC interface, overriding PCB controls. Settings stored on PCB in non-volatile memory. • 24VDC output for Pressure Sensor supply. 26