15
Voltage inputs
Instruction book, IQAN
Connecting a 2-wire temperature sensor to voltage in
When you connect a PTC (positive temperature coefficient) temperature sensor you
may need to use a pull up resistor on the input signal. Please check the technical data
for your specific temperature sensor.
Connecting switches to the voltage inputs using VREF
Switches could be connected to the voltage inputs, to create a digital on/off signal. The
switches should be connected to +VREF and VIN/DIN respectively for 5V signal. The
current consumption for the input is negligible.
N
OTICE
Maximum load for VREF position, see "Appendix A".
EXAMPLE
Connect the negative terminal of the temperature sensor to -VREF, and the signal to
VIN-X. The pull up resistor will be connected between VIN-X, and +VREF.
Connecting -VREF and temperature sensor signal VIN-X.
The pull up resistor value for a R
25
=2000
PTC sensor is 4,7 K
EXAMPLE
Connect the positive and negative terminals of the switch to +VREF, and VIN-X,
respectively.
Connecting a switch to VIN-X and VREF.
-VREF
VIN-X
+VREF
IQAN module
Sensor
pull up
VIN/DIN-X
+VREF
IQAN module
switch
