How to identify whether temperature sensor is RTD or Thermocouple?
1.Lead Wires
RTD has two,three or four leads per sensing element Thermocouple has two leads per junction RTD typically have red,white,green or black leads TC color match thermocouple type- red(common),yellow,purple,blue,white.
2.Resistance check
RTD will have about 109 ohms between leads at 20 deg C Thermocouple lead resistance is typically less than 1 ohm
3.Continuity check
TC grounded junction has path from leads to case
4.Magnet test
RTD leads are not magnetic TC type J has one iron lead which is highly magnetic