Sharp R-967 Service Manual page 15

sor Cook, POTATO, and INSTANT ACTION are auto-
matic cooking functions.
POWER OUTPUT REDUCTION
After the same cooking mode is carried out for more than
the basis cooking time, the power output is automatically
reduced by turning the control relays on and off intermit-
tently, as shown in the table below. This is to protect the
oven door against temperature rising.
Basis cooking
Cooking mode time (minutes)
Microwave (100%) 20
Grill 15
Convection
Micro. (70%) 40 (Micro.)
+ Grill 15 (Grill)
D
U
Micro. (100%) 15 (Micro.)
A
+ Grill 15 (Grill)
L
Micro. (70%) 40 (Micro.)
+ Conv.
NOTE:
1. If the multiple sequence cooking is carried out in the
same mode, the basis cooking time is calculated from
the first.
2. Even if the cooking is stopped by the STOP key or
opening the door, the basis cooking time is calculated
from the first.
3. If the same cooking mode is repeated within 1 minute
and 15 seconds, the basis cooking time is calculated
from the first.
4. If the same menu of Automatic Cooking is repeated
within 1 minute and 15 seconds, the power output of
the microwave or the grill will be reduced to 70% after
20 minutes when the oven is started at first.
FAN MOTOR OPERATION (in Grill, Convection
and Dual mode)
When oven is stopped during cooking, or after the cooking
is completed, the fan motor will operate if the oven cavity
temperature is above 120˚C, and the fan motor will stop if
the oven cavity temperature is below 105˚C.
CONVECTION MOTOR OPERATION
If the temperature of oven cavity is higher than 120˚C
after and when operated by 250˚C convection cooking,
250˚C dual convection cooking or 250˚C preheating, the
convection motor will operate for maximum 1 minute until
the oven cavity temperature drops below 105˚C.
ABSOLUTE HUMIDITY SENSOR (AH SENSOR)
COOKING CONDITION
When the AH sensor is used, the foods are cooked in
microwave cooking mode without figuring time, power
level or quantity. When the oven senses enough steam
OPERATION SEQUENCE
Reduced power Time base
output (%) (seconds)
70 32
70 48
No reduction
50 48
50 48
50 48
50 48
50 48
No reduction
from the food, it relays the information to its microproces-
sor which will calculate the remaining cooking time and
power level needed for best results.
When the food is cooked, water vapour is developed.
The sensor "senses" the vapour and its resistance in-
creases gradually. When the resistance reaches the value
set according to the menu, supplementary cooking is
started. The time of supplementary cooking is deter-
mined by experiment with each food category and input-
ted into the LSI.
An example of how sensor works:
1. Potatoes at room tem-
perature. Vapour is
emitted very slowly.
2. Heat potatoes. Moisture
and humidity is emitted
rapidly. You can smell
the aroma as it cooks. ;
3. Sensor detects mois-
ture and humidity and
calculates cooking time
and variable power.
AH SENSOR COOKING SEQUENCE
1. When the AH sensor cooking condition is started, the
coil of shut-off relays (RY1+RY6) are energized, the
oven lamp and cooling fan motor are turned on, but the
power transformer is not turned on.
NOTE: The oven should not be operated on AH SENSOR
COOKING immediately after plugging in the unit.
Wait two minutes before cooking on AH SENSOR
COOKING CONDITION.
2. After about 16 seconds, the cook relay (RY2) is ener-
gized. The power transformer is turned on, microwave
energy is produced and first stage is started. The 16
seconds is the cooling time required to remove any
vapour from the oven cavity and sensor. (Figure O-2)
NOTE: During this first stage, do not open the door or
touch STOP pad.
3. When the sensor detects the vapour 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.
NOTE: In case where a small quantity of food is cooked,
the oven will stop without displaying the remaining
cooking time.
4. When the timer reaches zero, an audible signal sounds.
The shut-off relay (RY1+RY6) and cook relay (RY2)
are de-energized and the power transformer, oven
lamp, etc. are turned off.
5. Operating the door or touching the STOP pad, the time
of day will reappears on the display and the oven will
revert to an OFF condition.
9
AH SENSOR