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This post was last edited by Instrument Industry Observer on 2020-4-10 at 15:46. How to adjust the flow rate of an electromagnetic flowmeter? The electromagnetic flowmeter itself has this function, allowing for manual adjustment of the flow rate and pipe diameter. The specific steps are as follows: First, enter the menu of the electromagnetic flowmeter using the password, then locate the diameter setting. For example, if the diameter is DN50 and you want to increase the flow rate, change the diameter from DN50 to DN65; naturally, the flow rate will then be higher than that when the diameter is DN50. Another method for adjusting the flow rate exists as well: enter the password to access the menu, then find the K coefficient field. For example, if the K coefficient is 1.065, increasing this value will result in a higher flow rate; the larger the value of the K coefficient, the greater the flow rate will be. That is how to adjust the flow rate of an electromagnetic flowmeter. Those who are not trained staff should not alter the flow rate settings; if such adjustments are made, the electromagnetic flowmeter will give inaccurate readings. How to calibrate an electromagnetic flowmeter: After purchasing an electromagnetic flowmeter, if calibration is necessary, the following guidelines are provided by the author: Before calibrating the electromagnetic flowmeter, it is essential to thoroughly inspect the pipeline and the flowmeter itself, including removing any debris from the pipeline; pipelines carrying oily media do not require drying treatment. The checks prior to debugging also include an inspection of the electrical wiring of the device. First, it is necessary to test the connections in the wiring to ensure reliable grounding before proceeding with other tests on the wiring; this is to avoid capacitive effects in the wiring that could store electrical charge, or to prevent the power supply from causing damage to the instrument. In addition, insulation resistance and grounding resistance tests are also required. Water flow testing: Whether it is instruments for measuring aqueous medium suspensions or those for oily media, electromagnetic flowmeters should undergo water flow testing before formal commissioning, by simulating the actual conditions such as temperature, pressure, and flow rate of the medium to be measured. If any abnormalities occur during the water flow test, or if parameters are missing, the instrument should be tested individually or sent to the manufacturing unit for calibration. System test: After completing the individual function water-flow tests for the electromagnetic flowmeter and finishing all preliminary adjustments of the control unit, system testing can be carried out. Oil-based medium pipelines must be dried before the medium to be tested can be introduced for system operation. During system debugging, the host should first perform a coded scan of each measurement point to ensure that all instrument components are operating properly before proceeding with functional debugging. During functional debugging, the host system reads the parameters of each instrument, conducts critical value alarm tests, etc., then writes control data, carries out debugging one by one, and sends the relevant data to the corresponding upper-level computer for analysis. How to set the parameters of an electromagnetic flowmeter: Generally, it is necessary to set the parameters of an electromagnetic flowmeter, but many people are not aware of how to do this. Here, I will briefly explain how to set the parameters of an electromagnetic flowmeter. The general parameters are set within certain ranges, and there are differences among different manufacturers; the product manual should be followed in this regard. The electromagnetic flowmeter sensor makes judgments by measuring the resistivity of the fluid in real time. Whether the pipe is full or not; therefore, the measurement value for an empty pipe is a continuous value. Although different fluids have different resistivity values, this still allows us to determine whether the pipe in the flow meter is full or not, and thus the measurement value for an empty pipe remains a continuous value. Although different fluids have different resistivity values, as long as the fluid is in a full-pipe condition, its resistivity value remains stable. The LDG type electromagnetic flowmeter calculates the volumetric flow rate based on the small electromotive force corresponding to the fluid flow velocity, and is capable of outputting a 4-20mA current signal. To ensure the acquisition of accurate signals, three parameters must be set: the flowmeter diameter, the flow range, and the electromagnetic flowmeter coefficient. Among these parameters, both the path length and the coefficients of the electromagnetic flowmeter are set before the instrument leaves the factory; therefore, users cannot adjust these two parameters. Users can also set the flow range before the electromagnetic flowmeter is manufactured, and this setting can only be changed again if the user requests it. An electromagnetic flowmeter defines the resistivity value of a fluid when the pipe is filled at 100%; that is, when the pipe is full of fluid, the measurement value for an empty pipe is calibrated to 100% using the alarm threshold for an empty pipe. When the fluid level in the pipe of the electromagnetic flowmeter is below the measuring electrodes, the resistivity of the flowmeter increases when the electrodes come into contact with air. When the value exceeds the air traffic control alarm threshold, the electromagnetic flowmeter will display an air traffic control alarm signal, which is determined based on actual usage conditions. When the pipe is filled with fluid, the empty-pipe reading of the electromagnetic flowmeter can be calibrated to 100%; whereas when the liquid level in the pipe is entirely below the electrodes of the flowmeter, its empty-pipe reading will exceed 1000%. Therefore, when setting the empty tube alarm value for electromagnetic flowmeters at around 900%, it is possible to determine the status of the empty tube.