Npaq MR Hardware Manual
Installation and Configuration
2.4.3. Thermistor Input
The thermistor input is used to detect a motor over temperature condition by using a positive temperature
coefficient sensor. As the temperature of the sensor increases, so does the resistance. Under normal
operating conditions, the resistance of the thermistor is low (i.e., 100 ohms) which will result in a low input
signal. As the increasing temperature causes the thermistor’s resistance to increase, the signal will be seen
as a logic high triggering an over temperature fault. The nominal trip value of the sensor is 1k Ohm.
Table 2-12:
Thermistor Interface Pin Assignment
Pin#
Description
In/Out/Bi
2
Motor Over Temperature Thermistor
Input
Figure 2-19:
Thermistor Input
32
Chapter 2
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