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Controller Description
CONTROLLER DESCRIPTION
CONTROLLER DESCRIPTION
The MP-4000 is an advanced microprocessor
controller. It has been specially developed for
the control and monitoring of refrigeration
units. The controller contains the following
basic features:
Temperature/Message Status Display:
• Temperature area. Displays Return air
sensor, Supply air sensor, and Setpoint
• Message area. Displays Alarms, Message
and Controller menu
Keypad:
• F1 – F4 Function keys navigate within the
Status Display
• 2 Status LED indicators
• Special Function keys. ON/OFF, PTI,
Defrost
Controller Back-up Battery
Every Controller has a Back-up Battery. This
will allow the controller to be energized if the
unit is not connected to shore power. The
technician can change settings in the controller
- Setpoint, etc.
Press the ON/OFF key, the controller will
energize and stay energized for 25 sec, by
pressing any of the Menu keys the 25 sec timer
will reset to 20 sec.
Controller Input and Output Signals
The MP-4000 microprocessor controls all unit
functions to maintain the cargo at the proper
temperature. The controller also monitors and
records system faults and performs pretrip.
The MP-4000 controller uses advanced
solid-state integrated circuits to monitor and
control unit functions. The controller monitors
inputs from:
• Return Air Sensor
• Supply Air Sensor
• Evaporator Coil Sensor
• Condenser Coil Sensor
• Ambient Sensor
• Humidity Sensor
• USDA (Spare) Sensors 1, 2 and 3
• Compressor Discharge Line Temperature
Sensor
• High Pressure Cutout Switch/Discharge
Pressure Sensor
• Low Pressure Cutout Switch/Suction
Pressure Sensor
• Phase measuring circuits
• Current measuring circuits
• Voltage measuring circuits
Output signals from the controller
automatically regulate all unit functions
including:
• Compressor operation
• Condenser fan operation
• Evaporator fan motor operation
• Compressor digital valve
• Vapor injection valve
• Dehumidify valve
• Electric heaters
• Phase selection
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