First, the structure of differential pressure transmitter
Generally speaking, differential pressure transmitter is used with pressure guide tube. No matter what type of differential pressure transmitter, its positive pressure chamber and negative pressure chamber have components such as drain valves. Due to this structure, the calibration process of differential pressure transmitter becomes simple.
For the calibration of differential pressure transmitter, among the three groups of valves, the balance valve should be kept open, and the positive valve and negative valve should be kept closed; Second, exhaust cock and other parts; Third, replace the above components with connectors to keep the connection with the pressure source; Fourth, check the overall sealing situation; Fifth, connect the HART communicator with the output circuit.
Second, the voltage transformer calibration steps
1, fine tuning.
In the field calibration of voltage transformer, the main processes can be summarized as: damping zero adjustment, zero adjustment-full scale adjustment.
In actual production, in order to ensure the accuracy of calibration results, fine-tuning can be carried out first. The fine-tuning signal current should be kept within the range of 4-20mA. The sensing element of differential pressure transmitter has nothing to do with this practice, so there is no need for external pressure signal source in the process of fine adjustment. In addition, the purpose of fine-tuning is to influence the converter inside the differential pressure transmitter, so as to correct it.
2, secondary fine-tuning.
Different from fine adjustment, in order to ensure the consistency between the actual pressure signal and its signal current, a pressure signal source is needed in the adjustment process.
3. Weighting interval.
In this process, many people will have such misunderstandings. They think that the HART communicator can complete the range change without pressure source input. In fact, the use of standards is very important in range calibration, which can effectively prevent the occurrence of incorrect calibration.
Signature: Manufacturer of liquid level transmitter and pressure transmitter.