Sensor Cooking Condition - Sharp R-1514F Supplemental Service Manual

R-1514

SENSOR COOKING CONDITION

Using the Sensor Cooking function, the foods are cooked or
defrosted without figuring time, power level or quantity. When
the oven senses enough steam from the food, it relays the
information to its microprocessor which will calculate the
remaining cooking time and power level needed for best
results. When the food is cooked, water vapor is developed.
The sensor "senses" the vapor and its resistance increases
gradually. When the resistance reaches the value set accord-
ing to the menu, supplementary cooking is started. The time
of supplementary cooking is determined by experiment with
each food category and inputted into the LSI.
An example of how sensor works
(Baked potatoes):
1. Potatoes at room temperature.
Vapor is emitted very slowly.
2. Heat potatoes. Moisture
and humidity is emitted
rapidly. You can smell the
aroma as it cooks.
NOTE: " " indicates components with potential above 250V.
CAVITY
THERMAL CUT-OUT
FUSE
20A
A5
B5
HOOD FAN
THERMAL High
CUT OUT
B7
GRN
B9 Low
HOOD
GND
120 V AC.
CAPACITOR
60 Hz
HOOD
A1
MOTOR
HL
AH SENSOR
MAGNETRON
TEMPERATURE FUSE
CONTROL UNIT
N.O.
RY4
RY6
RY3
N.C.
OVEN LAMP
RELAY
RY1
RY5
N.O. COM.
A3 B1 B3
HOOD
LAMP
OL
HL
Figure O-1. Oven Schematic-Off Condition
3. Sensor detects moisture and humidity and calculates
cooking time and variable power.
Cooking Sequence.
1. Operate the oven in sensor cooking mode by referring to
operation manual.
NOTE: The oven should not be operated on Sensor Cooking
immediately after plugging in the unit. Wait two
minutes before cooking on Sensor Cooking.
2. The coil of shut-off relay (RY1) is energized, the oven
lamp, turntable motor and cooling fan motor are turned
on, but the power transformer is not turned on.
3. After about 32 seconds, the cook relay (RY2) is energized.
The power transformer is turned on, microwave energy
is produced and first stage is started.
The 32 seconds is the cooling time required to remove
any vapor from the oven cavity and sensor.
NOTE: During this first stage, do not open the door or touch
STOP/CLEAR pad.
4. When the sensor detects the vapor emitted from the
food, the display switches over to the remaining cooking
time and the timer counts down to zero.
At this time, the door may be opened to stir food, turn it
or season, etc.
5. When the timer reaches zero, an audible signal sounds.
The shut-off relay and cook relay are de-energized and
the power transformer, oven lamp, etc. are turned off.
6. Opening the door or touching the STOP/CLEAR pad, the
time of day will reappear on the display and the oven will
revert to an OFF condition.
COM.
E2
DOOR
SENSING
SWITCH
E1
RY2
F1
SECONDARY
INTERLOCK
F2
RELAY
F3
TTM FM
PRIMARY
INTERLOCK
SWITCH
6
SCHEMATIC
NOTE: CONDITION OF OVEN
1. DOOR CLOSED.
2. CLOCK APPEARS ON DISPLAY.
POWER
TRANSFORMER
HIGH VOLTAGE
CAPACITOR
0.94µF/ AC2300V
HIGH VOLTAGE
RECTIFIER