Every instrument manufacturer cannot guarantee that every instrument sold can achieve zero fault, which is related to the structure of the instrument and the operation habits of the field operators.The measurement parameters of the field instrument are generally divided into four parameters, namely temperature, pressure, flow rate and liquid level.First of all, before analyzing and inspecting the fault of the field instrument system, it is necessary to know the load of production and the parameter changes of raw materials from the field operator, check the recording curve of the fault instrument, and conduct a comprehensive analysis to determine the cause of the fault of the instrument.Secondly, before analyzing the fault of the field instrument, it is necessary to thoroughly understand the design scheme and intention of the instrument system, the structure, characteristics, performance and parameter requirements of the instrument system, as well as the production process, production process and conditions of the relevant instrument system.

When the indication value of the liquid level control instrument system changes to or * hours, the instrument can be checked first to see whether it is normal. If the indication is normal, change the liquid level control to manual remote control to see the change of the liquid level.If the liquid level can be stable in a certain range, the fault is in the liquid level control system;If the liquid level is not stable, it is generally the fault caused by the process system.When the indication of the differential pressure level control instrument is not in line with the indication of the field direct reading indicator, first check whether the field direct reading indicator is normal. If the indication is normal, check whether the sealing liquid of the negative pressure guide pipe of the differential pressure level instrument is leaking.If there is leakage, re-sealing fluid, zero adjustment;No leakage, maybe the negative migration of the meter is wrong, readjust the migration to make the meter indicate normal.