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Design and function
2016-03-10 / DIS 184_58300000140186_ara_en_k
Copyright by BSH Hausgeräte GmbH
Page 25 of 181
3.9
Cooking compartment temperature sensor
(Pt500 / Pt1000)
The cooking compartment temperature sensor measures the temperature in the
cooking compartment.
The electronics switches the cooking compartment heating elements on and off
based on the desired cooking compartment temperature.
The cooking compartment temperature sensor is located in a pipe that is attached
to the back wall of the cooking compartment and protrudes into the cooking
compartment.
3.9.1
Structure
Fig. 22:
Components of the cooking compartment temperature sensor (Pt500 /
Pt1000)
1
Connector
3
Platinum resistor
2
Connecting cables
4
Protective tube
Cooking compartment temperature sensors are temperature sensors that use
the dependence of the electrical resistance on the temperature in platinum as a
measuring effect.
For protection, the platinum measuring resistance is in a standardised cabinet or
protective tube.
Platinum measuring resistances are described according to their material (platinum
= Pt) and nominal resistance
R
0
at a temperature of 0 °C.
•
Pt500 (
R
0
= 500 Ω)
•
Pt1000 (
R
0
= 1 kΩ)
3.9.2
Function
Platinum measuring resistances are PTC resistors with a
P
ositive
T
emperature
C
oefficient =
PTC
.
A positive temperature coefficient means that the electrical resistance rises with
increasing temperature.
Fig. 23:
Function of the PTC
The PTC converts the temperature of the cooking compartment to electrical
resistance.
The electronics evaluates the resistance of the PTC and actuate a switching
process if the setpoint temperature of the cooking compartment is exceeded or
drops below the minimum.