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I. Product Overview A differential pressure transmitter is a device that converts differential pressure values into standardized output signals suitable for transmission. It is used to measure the level, density, and pressure of liquids, gases, or vapors, and then converts these values into 4–20mA DC signals for output. Moreover, there is a certain continuous functional relationship (usually a linear function) between its output signal and the differential pressure variable. It is mainly used for the measurement and control of differential pressure parameters in industrial processes. II. Product calibration: The on-site calibration of differential pressure transmitters is an important task for metrology personnel in industrial and mining enterprises. The general method involves removing the connection pipes of the transmitter, applying a standard pressure value to the high-pressure side, and allowing the low-pressure side to be in contact with the atmosphere. For different pressure differences, the transmitter will output a corresponding current value. The difference between this current value and the standard current value represents the error of that transmitter. The meter readers use various adjustment methods to keep this difference within the allowable range. Currently, electric differential pressure transmitters are used, and their calibration methods are mainly divided into two parts: one is the adjustment of parameter values and stability before the products leave the factory ； Second is the performance tuning of the product after it leaves the factory and is put into use. Pre-production debugging: 1. Connect the wires correctly; supply power only after verification that everything is in order. 2. Before applying pressure to the positive pressure chamber, adjust the zero point so that the current output is 4 mA. 3. Apply pressure to the positive-pressure chamber to the range value; if the measured current is 20mA, then it is fine; otherwise, adjust the range. 4. After repeating steps 2 and 3, verify that the zero point and range are correct. 5. Check the backlash. 6. Calculate the error. Adjustment during use after leaving the factory: 1. Drainage of the pressure transfer pipes: (1) Open the pressure-taking valves on both sides of the balance flow meter (Note: The valves must be fully opened) ； (2) Close the positive and negative pressure valves on both sides of the three-valve assembly, and open the balance valve in the middle ； (3) Open the unvalved positive and negative pressure ports on both sides of the pressure lead pipe to drain waste fluid. Clean the pressure guiding tube. 2. Condensation in the pressure tap tube: (1) When there is sufficient condensate water in the pressure tap tube, the positive and negative pressure valves on both sides of the three-valve assembly can be opened (with the balance valve in the middle remaining open), allowing the condensate water to flow into the positive and negative pressure chambers of the differential pressure transmitter. (2) Close the drain valve and allow the medium to condense naturally in the pressure guiding pipe until the entire pipe is filled with condensed water (this takes approximately 4 hours). 3. Venting of the differential pressure transmitter: This ensures that any residual air in the positive and negative chambers of the differential pressure transmitter is completely removed. 4. Zeroing of the differential pressure transmitter: (1) Close the exhaust valves on the positive and negative chambers of the differential pressure transmitter. (2) Close the positive and negative pressure valves on both sides of the three-valve assembly. 5. Flow measurement: Open the positive and negative pressure valves on both sides of the three-valve assembly, and close the balance valve in the middle to enter the measurement mode. 6. After the differential pressure transmitter has been calibrated, the valves on the high-pressure and low-pressure sides should be opened in a specific sequence. The correct way to operate it is to first open the balance valve, then the high-pressure valve; after that, close the balance valve and open the low-pressure valve. Such an order of activation prevents the transmitter from being subjected to the forces resulting from the opening of the valves on the high and low pressure sides, thereby extending its service life. The above are the same methods for calibrating differential pressure transmitters before and after leaving the factory; I hope this will be helpful to everyone. If you still have questions, please call Jiangsu Huike Automation Instrument Co., Ltd.