Program Control Unit; System Structure - Electrolux W4400H Service Manual

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Program control unit
This chapter describes the components which are specific to this washer
extractor. For a general description of the CPU board, display board and I/
O board(s), consult the service manual for the Clarus Program Control Unit.
System structure
CPU board
The machine's wash programs are stored in the CPU board memory. The
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CPU board controls the various washer extractor functions with the aid of
the program data and signals from the control panel buttons.
The CPU board communicates with the display board, motor control unit
and the three I/O boards via serial interfaces.
The CPU board has its own level switch and inputs from temperature sen-
sors.
I/O boards
The I/O boards receive information from the CPU board concerning the
outputs which are to be controlled. The I/O boards can control the follo-
wing functions:
I/O board 1:
door lock, water valves - cold and hot water, flush 1, drain 1, detergent
dispensing 1-4, external detergent dispensing 1-4 and heating relay 1.
I/O board 2:
water valves - cold, hard water and tank 1, drain 2, detergent dispen-
sing 5, external detergent dispensing 5-11, heating relay 2 and stop
valve drain 1.
From the I/O boards' inputs, the CPU board receives information om the
door lock switch, door status switch, (where applicable) external start/stop
and pause signals, low oil level and signals from tilt sensors and the tilt
control unit.
Control unit