Parameter listing and descriptions
263
ACH550-01 User's Manual
Code Description
Range
3501
SENSOR TYPE
0…6
Identifies the type of the motor temperature sensor used, PT100 (°C),
PTC (ohms) or thermistor.
See parameters 1501
AO
1
CONTENT
SEL
and 1507
AO
2
CONTENT
SEL
.
0 =
NONE
1 = 1 x PT100 – Sensor configuration uses one PT100 sensor.
• Analogue output
AO
1 or
AO
2 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
analogue input
AI
1 or
AI
2 and converts it to degrees Celsius.
2 = 2 x PT100 – Sensor configuration uses two PT100 sensors.
• Operation is the same as for above 1 x PT100.
3 = 3 x PT100 – Sensor configuration uses three PT100 sensors.
• Operation is the same as for above 1 x PT100.
4 = PTC – Sensor
configuration uses one PTC.
• The analogue output feeds
a constant current through
the sensor.
• The resistance of the
sensor increases sharply
as the motor temperature
rises over the PTC
reference temperature
(
T
ref
), as does the voltage
over the resistor. The
temperature measurement
function reads the voltage
through analogue input
AI
1
and converts it into ohms.
• The table below and the graph above show typical PTC sensor
resistance as a function of the motor operating temperature.
Excessive
Normal
T
Temperature
Resistance
Normal
< 1.5 kohm
Excessive
>
4
kohm
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