Preparation and debugging before operation

As with ordinary meters, after the installation and wiring of the electromagnetic flowmeter are completed, and before it is put into operation, you should check whether the following installation and wiring are correct and whether the meter can work normally. It must be emphasized here that for some units lacking experience, the installation and operation personnel of the instrument should carefully read the relevant technical instructions in the installation and operation manual of the electromagnetic flowmeter. The same as the usual instrument, after the installation and wiring of the electromagnetic flowmeter, Before putting into operation formally, you should check the following installation, wiring is correct, whether the instrument can work normally. It must be emphasized here that for some units lacking experience in use, the instrument installation and operation personnel should carefully read the relevant technical instructions in the relevant electromagnetic flowmeter installation and operation manual, and be good at analyzing and thinking about the problems encountered during the initial operation. The whole set of electromagnetic flowmeter has been adjusted and calibrated on the flow calibration device of the manufacturer. As long as the matching number of the sensor and the converter and the meter coefficient are checked, it can be put into operation without any adjustment. Mess up the entire set of instruments that have been adjusted. Before the instrument is put into operation, the sensor must be filled with the actual measuring medium, and the zero point should be adjusted in a static state after power-on. After being put into operation, the zero point should be checked regularly by stopping the flow according to the medium and use conditions. Especially for the non-clean medium that is easy to precipitate, easy to contaminate the electrode, and contains solids, check more at the beginning of the operation to gain experience and determine the normal inspection cycle. For qualified users, several basic parameters of the sensor should be measured and recorded before the instrument is put into operation. ①Insulation resistance of the electrode (when the sensor is empty, the two resistors are insulated against the instrument housing or ground); ②The insulation resistance of the excitation coil (the insulation resistance of the excitation coil to the instrument housing or the ground); ③The cold resistance value of the excitation coil ( That is, the copper resistance value of the enameled wire of the excitation coil); ④The contact resistance sensor of the electrode is filled with liquid, and the resistance value between the electrode and the grounding terminal is measured. The contact resistance value of the two electrodes should be roughly the same. These data are very helpful for the analysis of the cause of the sensor failure after a period of operation. For example, when the contact resistance of the two electrodes changes, it indicates that the electrodes are likely to be contaminated; the contact resistance increases, and the contamination may be insulating deposits; the contact resistance decreases, and the contamination may be conductive deposits The contact resistance of the two electrodes is asymmetry, which indicates that the two electrodes are polluted to different degrees; the decrease of the insulation resistance of the electrodes and the excitation coil indicates the degree of moisture of the sensor; when the insulation resistance drops to a certain level, it will affect the normal operation of the meter. The cold resistance value of the excitation coil is a parameter to ensure the normality of the excitation coil.