1. When the high-temperature pressure transmitter has no automatic temperature compensation at the reference end, the transmitter verifies the wiring.(1) Used when the high temperature pressure transmitter has no reference terminal temperature automatic compensation.(2) When the thermocouple high temperature pressure transmitter with compensation is calibrated by the practical measurement method, this wiring method is also used:Place a thermometer at the input end of the transmitter, measure the temperature of the cold junction, check the temperature potential value Eω from the index table, and then according to the potential value E0 of the thermocouple index table, the millivolt signal generator outputs (E0 -Eω) value, which is to simulate the output of the thermocouple, measure the 4-20mA current output value of the thermocouple high temperature pressure transmitter, and calculate the measurement accuracy of the transmitter. This method has two aspects: ambient temperature change and cold junction error measured by the thermometer, and cannot eliminate the measurement error caused by these two aspects. Therefore, it is usually used for on-site zero-time comparison measurement, not for verification of high-temperature pressure transmitters.2. Wiring when the high temperature pressure transmitter has automatic temperature compensation at the reference end(1) When the input signal is a thermocouple, check the wiring of the intelligent high temperature pressure transmitter according to this diagram. The wiring of high temperature pressure transmitters produced by other manufacturers is also the same.(2) The thermocouple compensation wire adopts the compensation wire corresponding to the measuring thermocouple; the mV signal generator is used to simulate the thermocouple signal; the ice cylinder container is in a mixed state of ice and water, and the cold junction temperature is maintained at 0°C.(3) Precise measurement method of high temperature pressure transmitter:According to the corresponding potential value on the thermocouple graduation table, the millivolt signal generator directly simulates the thermocouple output signal, measures the 4-20mA signal output by the high temperature pressure transmitter, and calculates the measurement accuracy of the transmitter.This measurement method can eliminate the measurement error caused by the temperature change of the cold junction during the measurement process, but the measurement error caused by the compensation line itself cannot be eliminated. This method is generally used in laboratory measurements and factory calibration of high temperature pressure transmitter manufacturers.
Post time: 21-09-21