Actual signals and parameters 217
Group 35: Motor temp meas
Group 35: Motor temp meas
Code Description Range Resolution Default S
3501
SENSOR TYPE
0…6 1 0
Activates the motor temperature measurement function and selects the sensor type.
See also parameter Group 15: Analogue outputs.
0 = NONE – Function is inactive.
1 = 1 x PT100 – Function is active. The temperature is measured with one Pt100
sensor. Analog output AO feeds constant current through the sensor. The sensor
resistance increases as the motor temperature rises, as does the voltage over the
sensor. The temperature measurement function reads the voltage through analog
input AI1/2 and converts it to degrees centigrade.
2 = 2 x PT100 – Function is active. The temperature is measured using two Pt100
sensors. See selection 1 x PT100 above.
3 = 3 x PT100 – Function is active. The temperature is measured using three Pt100
sensors. See selection 1 x PT100 above.
4 = PTC – Function is active. The
temperature is supervised using one
PTC sensor. Analog output AO feeds
constant current through the sensor. The
resistance of the sensor increases
sharply as the motor temperature rises
over the PTC reference temperature
(Tref), as does the voltage over the
resistor. The temperature measurement
function reads the voltage through
analog input AI1/2 and converts it into
ohms. The figure on the right-hand side
shows typical PTC sensor resistance
values as a function of the motor
operating temperature.
5 = THERM (0) – Function is active. The motor temperature is monitored using a PTC
sensor (see selection PTC) connected to a drive through a normally closed
thermistor relay connected to a digital input. 0 = motor overtemperature.
6 = THERM (1) – Function is active. The motor temperature is monitored using a PTC
sensor (see selection PTC) connected to a drive through a normally open
thermistor relay connected to a digital input. 1 = motor overtemperature.
See the figures in section Motor temperature measurement through the standard I/O.
Temperature Resistance
Normal 0 … 1.5 kohm
Excessive >
4 kohm