Thermo King CRR-40 119, Руководство пользователя

Страница: 55 / 170

MP-3000a Controller
55
Trip data from separate units is denoted by the
identification information entered into the
controller at the beginning of the trip via the
general purpose keypad. Identification data may
include the container ID number, location B.R.T.,
contents, loading data, voyage no., ship, load port,
discharge port and comments. The container ID
number is stored in the Configuration submenu.
General Theory Of Operation
The controller uses advanced solid-state
integrated circuits to monitor and control unit
functions. The controller monitors inputs from:
• Return air sensor
• Supply air sensor, left hand Supply air
sensor, right hand
• Evaporator coil sensor
• Condenser coil sensor
• Ambient sensor
• Humidity sensor
• USDA (Spare) sensors 1, 2 and 3
• Compressor discharge line temperature
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
• Liquid line solenoid valve
• KVQ valve
• Liquid injection valve
• Dehumidify valve
• Electric heaters
• Phase selection
Chill Loads (Setpoint at -9.9 C
[14.1 F] and Above)
The unit operates on Cool with Modulation and
Heat to provide accurate control of chill loads.
During Cool with Modulation, the controller uses
a proportional-integral derivative (PID) algorithm
and a KVQ valve to provide accurate control of
the container temperature in direct response to
load demand.
The KVQ valve is installed in the suction line and
controls the amount of refrigerant returning to the
compressor. The valve opens and closes in
response to a controller voltage pulse signal based
on a control temperature differential. The
controller uses the setpoint temperature, supply
air sensor temperature (left and/or right hand
sensors) and pull-down rate for the last 10
seconds, last 20 seconds and last 180 seconds to
calculate the control temperature differential.
Supply Air Sensor Control
Temperature control accuracy and protection
against frost damage is provided by using two
separate sensors (left hand and right hand) to
determine the supply temperature used to
calculate the control temperature differential:
• At setpoints below -1 C (30 F), the
controller uses the lowest supply air sensor
temperature.
• At setpoints above 0 C (32 F), the
controller uses the average temperature of
the left hand and right hand supply air
sensors.
• At setpoints between -1 C and 0 C (30 F
and 32 F), the con-troller uses a sliding
temperature scale from the lowest supply
air sensor temperature to the average
temperature of the left hand and right hand
supply air sensors.
If one supply air sensor fails, the controller uses
the temperature of the other supply air sensor for
temperature control. If both supply air sensors
fail, the controller uses the temperature of the
return air sensor plus an offset for temperature
control.