In the field use of differential pressure transmitter, how can we judge whether its working state is normal? Due to the faulty zero drift of the differential pressure transmitter and the blockage of the impulse pipe, the scale is rarely checked point by point in the field, but the zero point and change trend of the differential pressure transmitter are checked. The specific steps are as follows: Zero point check: close the positive and negative stop valves, open the balance valve, and the output current of the differential pressure transmitter should be 4mA. Check the change trend: After the zero point inspection of the differential pressure transmitter, each valve returns to its original state, and the blowdown valve of the negative pressure chamber is opened, and the output of the differential pressure transmitter should be the maximum. If the positive pressure blowdown valve is opened, the output is minimized. When the blowdown valve is opened, there is little or no discharge of the measured medium, indicating that the impulse pipe is blocked. The impulse pipe of the differential pressure transmitter should be dredged. When the differential pressure transmitter cannot work normally due to various reasons, our staff should make timely judgments on the site, find the cause of the failure, and investigate and solve it in time. Minimise losses throughout the production process.