Calibration method of measurement error of intelligent temperature transmitter
The intelligent temperature transmitter can collect and convert the real-time temperature of transformers, inductors, capacitors, arc suppression coils, bearings, windings and other equipment into automatic data, upload it to the background automation system, and provide a reliable basis for operators to monitor the equipment status. If the intelligent temperature transmitter fails, the displayed and uploaded temperature data will be wrong, causing the related equipment to malfunction or refuse to operate, making the operation and monitoring personnel unable to grasp the real-time temperature of the equipment. Therefore, it is of great significance to regularly verify the intelligent temperature transmitter to ensure the correctness of temperature data acquisition.
According to the relevant requirements of JJF 1183-2007 smart temperature transmitter calibration specification, the calibration items of smart temperature transmitter include: measurement error and insulation resistance measurement. Among them, the calibration of measurement error is divided into two ways: with sensor inspection and without sensor inspection. According to the actual experience in the field, the probability of failure of the thermal resistance, thermocouple and other detection elements of the intelligent temperature transmitter is relatively low, and the error introduced by this is not large.
Therefore, the calibration of the measurement error of the intelligent temperature transmitter usually adopts without the sensor. In the literature, the second-class standard mercury thermometer, constant temperature field, freezing point tank and other instruments and equipment are used to verify the measurement error of the temperature transmitter. Use thermal resistance and temperature transmitter to measure and output the temperature of the constant temperature field, and compare it with the value displayed by the second-class standard mercury thermometer, so as to realize the verification of the measurement error of the temperature transmitter. In the literature, instruments such as computers, standard platinum resistance thermometers and portable constant temperature baths are used to verify the measurement errors of temperature transmitters. The temperature control of the constant temperature bath is realized by the computer. After the temperature of the constant temperature bath is constant, the temperature of the constant temperature bath is measured by the temperature transmitter and compared with the value displayed by the standard platinum resistance thermometer, so as to realize the temperature transmission. Calibration of the measurement error of the instrument. In the literature, 4 resistors are used to simulate the test temperature, and 10 relays control the state of the circuit.
