ABB ACS880 Firmware Manual page 129

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The resistance of the PTC sensor increases when its temperature rises. The
increasing resistance of the sensor decreases the voltage at the input, and
eventually its state switches from 1 to 0, indicating overtemperature.
1...3 PTC sensors can also be connected in series to an analog input and an analog
output. The analog output feeds a constant excitation current of 1.6 mA through
the sensor. The sensor resistance increases as the motor temperature rises, as
does the voltage over the sensor. The temperature measurement function calculates
the resistance of the sensor and generates an indication if overtemperature is
detected.
For wiring of the sensor, refer to the Hardware Manual of the drive.
The figure below shows typical PTC sensor resistance values as a function of
temperature.
Ohm
4000
1330
550
100
+24VD
DI6
Program features 129
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