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.
Program features 91
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