R-950A
6
heater and convection motor are turn off.
6. Upon completion of the cooking time, the audible
signal will sound, and oven lamp, turntable motor,
cooling fan motor and grill heater are de-energized. At
the end of the grill cycle, the circuit to RY6 will be
maintained to continue operation of the cooling fan
motor for 3 minutes if the grill cooking time is longer
than 2 minutes, and if the cavity air temperature is
above 118˚C, the circuit to (RY6) will be maintained (by
the thermistor circuit) to continue operation of the
cooling fan motor until the temperature drops below
118˚C, at which time the relay will be de-energized,
turning off the fan motor.
7. At the end of the grill cook cycle, shut-off relay (RY4) is
energized turning on the damper motor. The damper is
returned to the open position, closing the damper
switch contacts which send a signal to the control unit,
de-energizing shut-off relay (RY4).
SIMUL GRILL COOKING CONDITION (Figure O-6)
Press the SIMUL GRILL pad. And then enter cooking time
by pressing the NUMBER pads. When the START pad is
touched, the following operations occur:
1. The numbers of the digital read-out start the count
down to zero.
2. The shut-off relays (RY1+ RY6) are energized, turning
on the oven lamp, turntable motor and cooling fan motor.
3. The shut-off relay (RY4) is energized.
The damper door is closed from the open position.
4. The power supply voltage is added to the grill heater
and power transformer at the same time.
5. The grill heater operates through the relay (RY7)
contacts and the power transformer operates through
the cook relay (RY2) contacts.
6. Upon completion of the cooking time, the audible
signal will sound, and oven lamp, turntable motor,
cooling fan motor, grill heater and power transformer
are de-energized. At the end of the simul grill cycle, the
circuit to RY6 will be maintained to continue operation
of the cooling fan motor for 3 minutes if the grill cooking
time is longer than 2 minutes, and if the cavity air
temperature is above 118˚C, the circuit to (RY6) will be
maintained (by the thermistor circuit) to continue
operation of the cooling fan motor until the temperature
drops below 118˚C, at which time the relay will be de-
energized, turning off the fan motor.
The relationship between the convection and microwave
power operations are as follows.
16 SEC.
32 SEC.
SIMUL GRILL
MICROWAVE POWER
= APPROX. 30%
ON
OFF
ON
(MICRO.)
(GRILL)
NOTE:
1) The Simul Grill is programmed with 30% microwave
power. The microwave power can be changed.
2) The relay (RY2) is operated by the CPU unit to supply
within a 48 second time base microwave energy.
3) During Simul Grill operation, the grill heater is
energized continuously. But after the Simul Grill
cooking exceeds 20 minutes, the RY2 will be de-
energized automatically turning off the power
transformer to protect the oven.
4) The ON and OFF time ratio does not correspond
with the percentage of microwave power, because
approx. 2 seconds are needed for heating of the
magnetron filament.
5) "SIMUL" means "Simultaneous".
AUTO COOK/AUTO REHEAT
AUTO COOK/AUTO REHEAT will automatically compute
and set the microwave power and cooking time. Select the
menu by touching the AUTO COOK/AUTO REHEAT pad.
Enter the weight / quantity by touching the Number pads.
When the START pad is touched, the oven works on
Microwave cooking mode according to the special cook-
ing sequence.
EASY DEFROST COOKING
The EASY DEFROST key is a special function key to
defrost meats and poultry faster and better. EASY DE-
FROST key has 4 defrost stages. EASY DEFROST auto-
matically defrosts roast beef, etc. When EASY DEFROST
is selected and the food weight is entered by using the
number pads, the oven will cook according to the special
cooking sequence. (Figure O-2)
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
during microwave cooking. This accomplished by the LSI
repeatedly measures the voltage across the temperature
measurement circuit (thermistor) during it's 32-seconds
time base comparing the obtained voltage measurements.
If the most recent voltage measured is 300mV grater 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, fan motor and convection motor. The LSI also
stops counting down and closes the damper door so that
no fresh air will enter the oven cavity. Please refer to the
following section for a more detailed description.
Operation
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 cooling fan 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 300mV the LSI makes the
judgment that there is a fire in the oven cavity and will
switch off the relays to the power transformer, fan
motor and convection 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 the "START" pad or the unit may be reset by
pressing the "CLEAR" pad.
