Description of the problem
This sensor changes its resistance with temperature variations. How to measure the resistance values of this sensor using the SIRIUS module?
Description of the solution
Thermistors are devices that are used to measure temperature and are while not often used with DEWESoft hardware they can still be configured to function with additional steps. In order to connect these to a DEWESoft STG/STGM/STGS channel the configuration in the channel setup needs to be a half bridge with calculations to get the output.
The most accurate way to connect the PTC Thermistor is to use the half-bridge option. To get the smallest possible error, the Rref should be as close to the PTC resistor as possible.
For this configuration the Rref should be connected to the positive excitation lines and the thermistor should be connected to the negative excitation lines, as follows:
If they are reversed where Rref is connected to negative excitation and the Thermistor is connected to positive excitation, the curve will be opposite of what is desired:
When connected correctly the measured temperature will move in the desired direction:
Additional information
- Some more information can be found in the attached document.