TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units as
shown in the block diagram.
(1) Relay unit
(2) Key unit
(3) Control unit
Exchange of signals between each unit is indicated by the ar-
rows in the block diagram. The principal functions of these
units and the signals communicated among them are explained
below.
Relay Unit
Relay unit consists of two Relays (RY1 and RY2), power source
circuit and buzzer circuit.
Key Unit
The key unit is composed of a matrix, signals generated in the
LSI are sent to the key unit through E8, El 2, El 3, El 5, El 6
and E17.
When a key pad is touched, a signal is completed through the
key unit and passed back to the LSI through AN4-AN7 to per-
form the function that was requested.
Control Unit
Control unit consists of LSI (IX2429YA), power source circuit,
synchronizing signal circuit, ACL circuit, buzzer circuit, AH sen-
sor circuit, temperature measurement circuit and indicator
circuit.
1)
2)
3)
4)
5)
LSI (IX2429YA)
This LSI controls the AH sensor signal, temperature meas-
urement signal, key strobe signal, relay driving signal for
oven function, and indicator signal.
Power Source Circuit
This circuit generates voltage [VC (for IX2429YA): - 5V,
VF +: - 18.5V, VF-: -22V, VA: - 15V and Vp: -27Vl
necessary in the control unit.
Synchronizing Signal Circuit
The power source synchronizing signal is available in order
to compose a basic standard time in the clock circuit.
It accompanies a very small error because it works on com-
mercial frequency.
ACL Circuit
Circuit to generate signals resetting the LSI to the initial
state when power is supplied.
Buzzer Circuit
The buzzer is responsive to signals from the LSI to emit
noticing sounds (key touch sound and completion sound).
6)
7)
8)
9)
-- t
Absolute Humidity Sensor Circuit
Temperature Measurement Circuit
The temperature of food is measured by the probe. The
probe has a thermistor built in whose resistance varies
with the temperature. The variation of resistance is de-
tected by the temperature measurement circuit.
Stop Switch
A switch to “tell” the LSI if the door is open or closed.
Relay Circuit
To drive the magnetron, fan motor, turntable motor and
light the oven lamp.
10) Indicator Circuit
Indicator element is a Fluorescent Display.
Basically, a Fluorescent Display is a triode having a
cathode, a grid and an anode. Usually, the cathode of a
Fluorescent Display is directly heated and the filament
serves as cathode.
The Fluorescent Display 6-digits, 13-segments are used
for displaying figures.
This circuit detects absolute humidity of food which is
cooking, to allow automatic cooking.
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