Outline Of Touch Control Panel; Key Unit; Control Unit - Sharp R-9H10 Service Manual

OUTLINE OF TOUCH CONTROL PANEL
The touch control section consists of the following units as
shown in the control panel circuit.
(1) Key unit
(2) Control unit
The principal functions of these units and the signals commu-
nicated 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 Pl , P02, P05, P07, P10,
Pl 1 and P13.
When a key pad is touched, a signal is completed through the
key unit and passed back to the LSI through RO - R3 to
perform the function that was requested.
Control Unit
Control . unit consists of LSI (IZA197DR), power source
circuit,
synchronizing signal circuit, ACL circuit, buzzer
circuit, temperature measurement circuit, absolute humidity
sensor 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 the voltages necessary for the control
unit from the AC line voltage.
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 signals resetting the LSl to the initial
state
when power is applied.
5) Buzzer Circuit
The buzzer is responds to signals from the LSI to emit
noticeable sounds (key touch sound and completion
sound).
6) Temperature Measurement Circuit [ 1 ] : Oven
The temperature in the oven cavity is sensed by the ther-
mistor.
The variation of resistance according to sensed temperature
is detected by the temperature measurement circuit and
the result applied to LSI.
The LSI uses this information to control the relay and dis-
play units.
7) Absolute Humidity Sensor Circuit
This circuit detects the humidity of the food which is be-
ing cooked, to control its automatic cooking.
8) Stor Switch
A switch to "tell" the LSI if the door is open or closed.
9) Relay Circuit
To drive the megnetron, heating element, fan motor,
convection motor, damper motor and light the oven lamp.
10) Indicator Circuit
Indicator element is a Fluorescent Display.
Basically, a Fluorescent Display is 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 has 6-digits, 15-segments are used
for displaying figures.
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