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FILE NO. SVM-03008
– 22 –
(1) Role of indoor unit controller
The indoor unit controller judges the operation
commands from the remote controller and
assumes the following functions.
• Judgment of suction air temperature of the
indoor heat exchanger by using the indoor
temp. sensor (TA sensor)
• Temperature setting of the indoor heat
exchanger by using heat exchanger sensor
(TC sensor) (Prevent-freezing control)
• Louver motor control
• Indoor fan motor operation control
• LED (Light Emitting Diode) display control
• Transferring of operation command signal
(Serial signal) to the outdoor unit
• Reception of information of operation status
(Serial signal including outside temp. data) to
the outdoor unit and judgment/display of error
(2) Role of outdoor unit controller
Receiving the operation command signal (Serial
signal) from the indoor controller, the outdoor unit
performs its role.
• Compressor operation
control
• Operation control of
outdoor fan motor
• P.M.V. control
• Detection of inverter input current and current
release operation
• Over-current detection and prevention
operation to IGBT module (Compressor stop
function)
• Compressor and outdoor fan stop function
when serial signal is off (when the serial signal
does not reach the board assembly of outdoor
control by trouble of the signal system).
• Transferring of operation information (Serial
signal) from outdoor unit to indoor unit
• Detection of outdoor temperature and
operation revolution control
• Defrost control in heating operation (Temp.
measurement by outdoor heat exchanger and
control for 4-way valve and outdoor fan)
8. OPERATION DESCRIPTION
8-1. Outlined of Air Conditioner Control
This air conditioner is a capacity-variable type air
conditioner, which uses DC motor for the indoor fan
motor and the outdoor fan motor. And the capacity
proportional control compressor which can change the
motor speed in the range from 13 to 110 rps is
mounted. The DC motor drive circuit is mounted to the
indoor unit. The compressor and the inverter to control
fan motor are mounted to the outdoor unit.
The entire air conditioner is mainly controlled by the
indoor unit controller.
The indoor unit controller drives the indoor fan motor
based upon command sent from the remote control,
and transfers the operation command to the outdoor
unit controller.
The outdoor unit controller receives operation
command from the indoor unit side, and controls the
outdoor fan and the pulse modulating valve. (P.M.V)
Besides, detecting revolution position of the
compressor motor, the outdoor unit controller controls
speed of the compressor motor by controlling output
voltage of the inverter and switching timing of the
supply power (current transfer timing) so that motors
drive according to the operation command. And then,
the outdoor unit controller transfers reversely the
operating status information of the outdoor unit to
control the indoor unit controller.
As the compressor adopts four-pole brushless
DC motor, the frequency of the supply power
from inverter to compressor is two-times
cycles of the actual number of revolution.
Operations followed
to judgment of serial
signal from indoor
side.