In view of the common faults of the metal tube float flowmeter during operation:1. Pointer jitter:1. Slight pointer jitter: Generally caused by medium fluctuations. It can be overcome by increasing damping. 2. Moderate pointer jitter: Generally caused by the flow of the medium. For gas, it is generally caused by unstable operating pressure of the medium. The pressure stabilization or flow stabilization device can be used to overcome or increase the gas damping of the float flowmeter. 3. Severe pointer jitter: Mainly due to medium pulsation, unstable air pressure, or pressure, temperature, and flow rate of the gas operating state given by the user that do not match the actual state of the float flowmeter. Large differences cause the float flowmeter to over-range.2. The pointer stops at a certain position and does not moveThe main reason is that the float of the float flowmeter is stuck. Generally, when the float flowmeter is used, the valve is opened too fast, so that the float quickly impacts the stopper, causing the stopper to deform and the float to be stuck. However, it does not rule out that the float guide rod and the stop ring are not concentric, causing the float to jam. When handling, disassemble the meter, remove the deformed stopper and reshape it, and check whether it is concentric with the guide rod. If it is not concentric, correct it, then install the float, push the float by hand, and feel that the float is unobstructed up and down. Yes, in addition, the float flowmeter must be installed vertically or horizontally, not inclined, otherwise it will easily cause the meter to jam and bring errors to the measurement.Three, the measurement error is large1. The installation does not meet the requirements;For the vertical installation of the float flowmeter, keep it vertical, and the inclination angle is not more than 20 degrees;For the horizontal installation of the float flowmeter, keep it level, and the inclination angle is not more than 20 degrees;There should be no ferromagnetic objects in the 100mm space around the float flowmeter;The installation location should be far away from the valve reducing port, pump outlet, process pipeline turning port, etc. The requirement of 250mm straight pipe section after the first 5D should be maintained.2. The large change in the density of the liquid medium is also a cause of the large error. Before the meter is calibrated, the medium is converted according to the density given by the user and converted to the flow of water in the calibrated state for calibration. Therefore, if the density of the medium changes greatly, it will cause a large error in the measurement. The solution can be to bring the changed medium density into the formula and convert it into an error correction coefficient, and then multiply the flow rate measured by the flowmeter by the coefficient and convert it to the real flow rate.3. Because the gas medium is greatly affected by temperature and pressure, it is recommended to use temperature and pressure compensation to obtain the true flow rate.4. Due to many factors such as long-term use and pipeline vibration, the movable parts of the float flowmeter, such as the sensing magnet, pointer, counterweight, and rotating magnet, become loose, causing large errors. Solution: You can verify by pushing the pointer first. First press the pointer at the RP position to see if the output is 4mA and the flow display is 0%, and then verify according to the scale in turn. If you find any discrepancies, you can adjust the position of the parts. Generally, professionals are required to adjust, otherwise it will cause the position to be lost and need to be returned to the manufacturer for calibration.Four, no current output 1. First check whether the wiring is correct. 2. Whether the LCD has display, if there is no output, the output tube is mostly broken and the circuit board needs to be replaced. 3. The calibration value is missing. Due to the E2PROM failure, the calibration data of the meter will be lost, and no output current will be caused, and the current will remain unchanged. Solution: The data recovery operation can be used. If it does not work, you can first set the data in the password 2000, and then set the data in the password 4011 by pushing the pointer by hand to calibrate the data from RP to 100%.5. No on-site display 1. Check whether the wiring is correct. 2. Check whether the power supply is correct. 3. Reinstall the LCD module and check that the contact is not real. 4. For multi-wire power supply mode, check whether terminals 12 and 13 are connected to an ammeter or are short-circuited. 6. The on-site LCD always displays 0 or full scale 1. Check the range and zero parameters set in the 2000 password. ZERO is required to be less than the value of SPAN, and the two values cannot be equal. 2. Check whether the sampled data is up, and push the pointer with your hand to watch the sample value change. If there is no change, it is generally because the circuit board sampling circuit is faulty, and the circuit board needs to be replaced.
Seven, the alarm is incorrect 1. Check that the deviation setting d value cannot be too large. 2. In the FUN function, whether the logic function is correct. HA-A represents the upper limit positive logic. LA-A means lower limit positive logic. 3. Check the setting size of the alarm value in the SU. 4. If the LCD bar code indication is correct and the output has no action, check whether the external power supply and the negative pole of the external power supply are connected to the negative pole of the power supply of the instrument. 5. The circuit board is faulty, replace the circuit board. Eight, the cumulative pulse output is not correct 1. Check whether the alarm value of the channel that selects the cumulative pulse output is set to zero. 2. The circuit board is faulty, replace the circuit board.
Post time: 21-09-21