23
R-1850
R-1851
TOUCH CONTROL PANEL ASSEMBLY
OUTLINE OF TOUCH CONTROL PANEL
3) Synchronizing Signal Circuit
The power source synchronizing signal is available in
order to compose a basic standard time in the clock
circuit. It incorporates a very small error because it works
on commercial frequency.
4) ACL Circuit
A circuit to generate a signals which resetting the LSI to
the initial state when power is applied.
5) Buzzer Circuit
The buzzer is responds to signals from the LSI to emit
audible sounds (key touch sound and completion sound).
6) Temperature Measurement Circuit : Oven
The temperature in the oven cavity is sensed by the
thermistor. The variation of resistance according to sensed
temperature is detected by the temperature measure-
ment circuit and the result applied to LSI. The LSI uses
this information to control the relay and display units.
7) Absolute Humidity Sensor Circuit
This circuit detects the humidity of a food which is being
cooked, to control its automatic cooking.
8) Door Sensing Switch
A switch to inform the LSI if the door is open or closed.
9) Relay Circuit
To drive the magnetron, heating element, fan motor,
convection motor, damper motor, turntable motor, hood
motor, and light the oven lamp and hood lamp.
10) Indicator Circuit
Indicator element is a Fluorescent Display.
Basically, a Fluorescent Display is triode having a cath-
ode, a grid and an anode. Usually, the cathode of a
Fluorescent Display is directly heated and the filament
serves as cathode.
The Fluorescent Display has 8-digits, 16-segments are
used for displaying figures.
The touch control section consists of the following units
as shown in the touch control panel circuit.
(1) Key Unit
(2) Control Unit
The principal functions of these units and the signals com-
municated among them are explained below.
Key Unit
The key unit is composed of a matrix, signals generated in
the LSI are sent to the key unit through P00 - P06.
When a key pad is touched, a signal is completed through
the key unit and passed back to the LSI through AN1 and
R24 - R27 to perform the function that was requested.
Control Unit
Control unit consists of LSI, power source circuit, synchro-
nizing signal circuit, ACL circuit, buzzer circuit, temperature
measurement circuit, absolute humidity sensor circuit, relay
circuit and indicator circuit.
1) LSI
This LSI controls the temperature measurement signal,
AH sensor signal, key strobe signal, relay driving signal
for oven function and indicator signal.
2) Power Source Circuit
This circuit generates voltages necessary for the control
unit from the AC line voltage.
Symbol
Voltage
Application
VC
-5.1V
LSI(IC1)
VP
-31V
Fluorescent display tube : Grid
and anode voltage
VF1
2.9Vac
Filament of fluorescent
dis play tube
VF2
(VF1 to VF2 voltage)
