Transmitter maintenance work

1) Touring inspection: the indication of the instrument, whether the indicated value of the instrument is abnormal; whether the air supply pressure of the pneumatic transmitter is normal; whether the power supply voltage of the electric transmitter is normal; the ambient temperature, humidity, and clean conditions; the instrument and process interface, and pressure guiding Whether there is leakage or corrosion between the pipe and the valve. 2) Regular maintenance: Regularly check the zero point and perform regular calibration; Regularly carry out sewage and discharge 1) Touring inspection: the meter indicates the status, whether the meter indicates whether the value is abnormal; whether the air pressure of the pneumatic transmitter is normal; the power supply of the electric transmitter Whether the voltage is normal; the ambient temperature, humidity, and cleanliness; whether there is leakage or corrosion between the instrument and the process interface, the pressure pipe and the valve. 2) Regular maintenance: Regularly check the zero point and perform regular calibration; regularly perform sewage, condensation, and venting; regularly purge the pressure guiding tube of the easy-to-block media, and regularly fill the isolating fluid. 3) Equipment inspection: Check the quality of the instrument to be accurate and sensitive. The indication error and static pressure error meet the requirements, and the zero position is correct; the instrument parts are intact, no serious rust or damage, the nameplate is clear and correct, and the fasteners are not allowed. Loose, the connectors are in good contact, and the terminal wiring is firm; the technical information is complete, accurate, and meets the management requirements. What is the concept of the working pressure difference range of a mass flow controller? A gas flow adjustment valve is installed in the mass flow controller (MFC), which can adjust the flow through the controller from zero to the full range of measurement during the working process. Among them, there will be a pressure drop between the inlet and the outlet of the controller, that is, a pressure difference. The working pressure difference range of MFC is usually 0.1～0.3MPa. If the pressure difference is lower than the minimum value (0.1 MPa), the control may not reach the full scale value; if it is higher than the maximum value (0.3MPa), the flow rate may be closed. It cannot be less than 2% FS. When the user uses the MFC, regardless of whether the user's working reaction chamber is vacuum or high pressure, the pressure difference between the inlet and outlet ends of the MFC should be kept within the required pressure difference range, and the pressure should be relatively stable.