(1) When the indication value of the flow control instrument system reaches the minimum, first check the on-site detection instrument. If it is normal, the fault is displayed on the instrument. When the indication of the on-site testing instrument is also the smallest, check the opening degree of the regulating valve. If the opening degree of the regulating valve is zero, it is often a failure between the regulating valve and the regulator. When the on-site detection instrument indicates the smallest and the opening degree of the regulating valve is normal, the failure may be caused by insufficient system pressure, blocked system pipelines, improper pump capacity, medium crystallization, and improper operation. If it is a fault in the instrument, the reasons are: the orifice differential pressure flowmeter may be a positive pressure induced pressure pipe block; the differential pressure transmitter positive pressure chamber is leaking; the mechanical flowmeter is a gear stuck or a filter blocked.
(2) When the indication value of the flow control instrument system reaches the maximum value, the detection instrument often indicates the maximum value. At this time, the remote control valve can be manually opened or closed. If the flow can be reduced, it is usually caused by process operation. If the flow value cannot be lowered, it is caused by the instrument system. Check whether the regulating valve of the flow control instrument system is operating; check whether the instrument measurement pressure system is normal; check whether the instrument signal transmission system is normal.
(3) The indicator value of the flow control instrument system fluctuates more frequently, and the control can be changed to manual. If the fluctuation is reduced, it is caused by the instrument or the PID of the instrument control parameter is not suitable. If the fluctuation is still frequent, it is the process operation Caused by.