Sharp R-4H55 Service Manual page 27

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R-4X55
R-lX55B
WEIGHTSENSOR CIRCUIT (R-4X55, R-4XX55B)
Turntable
Turntable Motor
Section View of Turntable
Weight
Sensor
support
Construction of W eight Sensor
Weight
6B"SW
Weight sensor circuit
This circuit works to weight the food by weight sensor during SENSOR DEFROST modes to set heating time. Piezo-
electric device is used in theweight detector section. When the roller below the turntable presses the knob, through oven
seal. the piezO-electric device generates the voltage according the load applied on the roller. Weight sensor and then
sent to A/D conversion input pin A5 inside of LSI. The LSI converts the value into weight and calculates the heating time.
Weight measurement is made by the three rollers passing on the knob, taking the average value of the voltage then
produced. This initial balancing is set up about 50 seconds afterunit is put in the Weight sensor cooking mode.
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