How to solve the problem of inaccurate thermocouple measurement values?

Inaccurate thermocouple measurements can be solved from multiple aspects, as follows:
Correct selection and installation
Reasonable selection: Select the appropriate type of thermocouple based on the measurement temperature range, environmental conditions and other factors. For example, K-type thermocouples are suitable for general industrial occasions and have a wide measurement temperature range; S-type thermocouples are often used for high-precision measurements and high-temperature environments.
Optimize the installation position: Install the thermocouple in a position that can accurately reflect the temperature of the object being measured, and avoid installing it in a dead corner of the air flow, near a heat source or a cold source. At the same time, ensure that the insertion depth of the thermocouple is sufficient, generally 8-10 times the diameter of the protective sleeve, to ensure that it fully senses the temperature of the measured medium.
Inspect and maintain the thermocouple
Regular inspection: Regularly inspect the appearance of the thermocouple to check whether the protective sleeve is damaged or cracked, and whether the electrode is discolored or deformed. If any problems are found, replace the thermocouple in time.
Cleaning and calibration: Clean the thermocouple regularly to remove dirt, dust and corrosion on the surface. At the same time, calibrate the thermocouple according to the prescribed cycle, compare it with a high-precision standard thermometer, adjust the deviation, and ensure accurate measurement.
Ensure correct and stable wiring
Correct wiring: Check whether the positive and negative poles of the thermocouple are connected correctly, whether the connection of the compensation wire and the thermocouple is matched, and avoid reverse or wrong connection. At the same time, ensure that the terminal is firm to prevent loosening.
Avoid interference: Lay the thermocouple wiring separately from the strong power line to avoid electromagnetic interference. If shielded wire is used, the shielding layer is grounded to reduce the impact of external interference on the measurement signal.
Control the cold end temperature
Constant temperature at cold end: Use the cold end constant temperature method to place the cold end in a constant temperature bath to keep the cold end temperature constant and reduce the impact of cold end temperature changes on the measurement.
Cold end compensation: Use appropriate cold end temperature compensation methods, such as calculation correction method, electronic compensation method, bridge compensation method, etc., to compensate for cold end temperature changes and ensure the accuracy of the measurement results.
Check measuring instruments
Instrument calibration: Calibrate and check the measuring instruments used with thermocouples to ensure the accuracy and function of the instruments. Such as whether the range setting of the instrument is correct, whether the display is accurate, etc.
Replace the instrument: If the instrument is faulty and cannot be repaired, a new measuring instrument should be replaced in time to ensure the normal operation of the measurement system.