Thermistor Input

The thermistor input is used to detect a motor over temperature condition by using a negative temperature coefficient sensor. As the temperature of the sensor increases, the resistance decreases. Under normal operating conditions, the resistance of the thermistor is high (10 kΩ, for example) which will result in a high input signal. As the increasing temperature causes the thermistor’s resistance to decrease, the signal will be seen as a logic low triggering an over temperature fault. The default trip value of the sensor is 2.4 kΩ, which corresponds to 60 °C. The trip point can be changed in the Automation1 software using the MotorTemperatureThreshold parameter.

Table 2-21:     Thermistor Input Pins on the Galvo Motor Connectors

Pin	Description	In/Out/Bi
9	Motor Over Temperature Thermistor	Input

Figure 2-16:     Thermistor Input Input Schematic