(1) When the value of the liquid level meter reaches the highest or lowest, judge according to the field detection meter. If the field meter is normal, change the system to manual regulation and check whether the liquid level changes; if the liquid level can be kept stable in a certain range, it means that there is a problem with the liquid level control system, and vice versa, it is due to the process.
(2) For differential pressure level meter, when the display data of the control instrument and field detection instrument do not match, and there is no obvious abnormality in the field instrument, check whether the liquid seal of the pressure guide tube is normal, if there is leakage, replenish the sealing liquid and zero the instrument; if there is no leakage, the initial inference is that the negative migration amount of the instrument is wrong and needs to be corrected.
(3) When the data of the level control instrument fluctuates abnormally, it should be judged according to the equipment capacity. If the equipment capacity is large, it is usually a problem with the instrument; if the equipment capacity is small, the process operation should be checked first.
If the process operation has changed, it is very likely that the fluctuation is caused by the process, and vice versa, it is a problem with the instrument.