Pt-100 or pt100 is one of the most used temperature sensor. It is one of the most used temperature sensor. Cheap but robust for use and capable to directly interface with PLC. The use of pt-100 is limited to below 150°c. And it is not suitable for internal use, with its hard plastic body as it has own limitation.
pt-100 temperature naming and working principle:
pt-100 is named as such because platinum is used as the sensing material and at with perfect calibration it has 100 ohm resistance at 0°c.
The zero scale for pt-100 is 100 ohm at 0°c. Thus the measuring value of pt-100 is resistance and for thermocouple temperature sensor measuring parameter is voltage. With the measuring value matching by chart the perspective temperature can be found.
In PLC programming for a certain pt-100, the temperature log chart with resistance is programmed, thus it can be used in automation system.
How to test Pt-100 temperature sensor
The checking of pt-100 temperature sensor is a matter of sense. In my power plant we checked pt-100 temperature, used to find 114ohm to 120ohm for functioning pt-100 (subject to ambient temperature being 30°c – 40°c)and for faulty pt-100 it used to be 0 ohm or infinite(open).
Pt-100 temperature sensors can be tested or checked to see if its working properly.The testing of Pt-100 requires a resistance meter or ohmmeter.
Open Pt-100 sensor cover to check:
Open the cap.
Use multimeter (resistance measurement).Take out one wire from PT-100 connection box.
Check Pt-100 sensor resistance:
Connect the multimeter between two connection pins.Measure the resistance. Compare measured resistance to the values in engine manual, If the value is not zero or infinite,the sensor is working ok.
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