FAQ (Frequently Asked Questions)

What is the impact when the insulation resistance of a resistance thermometer sensor decreases?

When resistance thermometer sensors are used at sites, their insulation resistance may decrease because of the impact of the installation place, degradation of insulators due to aging, humidity invasion during manufacturing, etc. In many cases, thermocouples can be used without any problems; however, what is the actual impact? Also, what is the allowable decrease in insulation resistance?

For details, please see the PDF file in FAQ of Temperature Measurement 100. The result of calculation with the calculation formula shown in the material is described below. In the same way as the thermocouples, if there is an insulation resistance of some hundreds of kΩ, a large error will not be generated.

Insulation Resistance - Error Calculation Example Here, RI: Insulation Resistance, Rt: Reference Resistance, Rx: Calculated Resistance

• Thermocouples/
  Compensating Cables
  • Thermocouple Measurement Principle
  • Standard Thermo-electromotive Force Table
  • Average Temperature Measurement with a Thermocouple
  • Color Codes of Compensating Cables
• Resistance Thermometer Sensors
  • Resistance Thermometer Sensor Measurement Principle
  • Resistance Thermometer Sensor Resistance Value Table
• Protection Tube-related
  • Thermowell Wake Frequency Calculation
  • Examples of Thermowell Wake Frequency Calculation ASME PTC 19.3-TW-2010 (PDF)
  • Thermowell Wake Frequency Calculation Input Sheet (Excel)
• Temperature Sensors in General
  • Instruction Manual in English (PDF)
  • Instruction Manual 2006/Included Version (PDF)
  • Temperature Sensor-related Standards (PDF)
• FAQ (Frequently Asked Questions)
• What is the impact when the insulation resistance of a thermocouple decreases?
• What will happen if a thermocouple (compensating cable) is connected with the wrong polarity?
• What is the impact when the sleeve temperature increases and the connection part of the thermocouple and compensating cable has a high temperature?
• What is the measurement error when a thermocouple is connected with a terminal or others?
• Since the distance from the thermocouple to the measuring instrument is far away, we use a compensating cable, but what is the influence on distance restriction and accuracy?
• What is the unavoidable error (SRO: Short Range Ordering) of the type K thermometer?
• What is the impact when the insulation resistance of a resistance thermometer sensor decreases?
• What is the cause when a resistance value defect or the wire inside the resistance thermometer sensor is disconncted?