Viking DMOR206SS Service Manual page 13

periment with each food category and inputted into the LSI.
An example of how sensor works:
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.
AH SENSOR
3. Sensor detects moisture and humidity and calculates
cooking time and variable power.
Cooking Sequence.
1. Touch SENSOR COOK, REHEAT or POPCORN pad.
When Sensor Cook is touched, to choose menu the
number pad should be touched.
NOTE: The oven should not be operated on SENSOR
COOK, REHEAT or POPCORN immediately after
plugging in the unit. Wait five minutes before cooking
on SENSOR COOK, REHEAT or POPCORN.
2. The coil of shut-off relays (RY1, RY4 and RY5) are
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.
CONVEC BROIL, CONVEC ROAST, CONVEC BAKE
CONVEC BROIL, CONVEC ROAST and CONVEC BAKE
will automatically compute the oven temperature, microwave
power and cooking time for broiling, roasting and baking. Set
the desired program by touching one of the CONVEC BROIL,
CONVEC ROAST or CONVEC BAKE pad, and number
pad. Enter the weight by touching the Number pads. When
the START pad is touched, the following operations occur:
1. The COOK indicator will light and the CONV or MIX
indicator will light.
2. The cooking time will appear on the display and start
counting down to zero. The cooking time is adjusted
automatically according to the weight of the food.
3. The shut-off relays (RY1, RY4, RY5 and RY7) are
energized, turning on the oven lamp, turntable motor,
cooling fan motor and convection motor. The power
supply voltage is applied to the heating element.
4. Now, the oven is in the convection cooking mode or
Automatic Mix Cooking condition.
5. When the oven temperature has reached the programmed
convection temperature, the oven goes into the
programmed cooking mode.
6. At the end of the cooking cycle, the damper is returned to
the open position and the oven will go to the off condition.
The cooling fan will remain on until the oven has cooled.
TIMED DEFROST COOKING
The DEFROST key is a special function key to defrost meats
and poultry faster and better. DEFROST automatically de-
frosts roast beef, etc.. When the DEFROST is selected and
the food weight is entered by using the DEFROST pad, the
oven will cook according to the special cooking sequence.
FIRE SENSING FEATURE (MICROWAVE MODE)
This model incorporates a sensing feature which will stop
the oven's operation if there is a fire in the oven cavity dur-
ing microwave cooking.
This is accomplished by the LSI repeatedly measuring
the voltage across the temperature measurement circuit
(thermistor) during it's 32-seconds time base comparing the
obtained voltage measurements. If the most recent volt-
age measured is 100mV greater than the previous voltage
measured, the LSI judges it as a fire in the oven cavity and
switches off the relays to the power transformer and fan motor.
The LSI also stops counting down and closes the damper
plate so that no fresh air will enter the oven cavity. Please
refer to the following section for a more detailed description.
Operation
The following operation will start 4 minutes after the start
pad is touched. Please refer to the timing diagrams below.
1. The thermistor operates within a 32-seconds time
base and it is energized for three (3) seconds and off
for 29 seconds. Two (2) seconds after the thermistor
is energized, the voltage across the temperature
measurement circuit is sampled by the LSI and twenty
one (21) seconds after the thermistor is cut off the LSI
turns on the convection motor for six (6) seconds.
2. The above procedure is repeated. If the difference
between the first voltage measured (in step 1) and the
voltage measured when the procedure is repeated (step
2) is greater than 100mV the LSI makes the judgment
that there is a fire in the oven cavity and will switch off
the relays to the power transformer and fan motor. The
LSI also stops counting down and closes the damper
door so that no fresh air will enter the oven cavity.
3. Once the fire sensor feature has shut the unit down, the
programmed cooking cycle may be resumed by pressing
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DMOR206SS