DM10 metal tube float flowmeter common faults and solutions

First, pointer jitter

1. Slight jitter: Generally caused by media fluctuations. It can be overcome by increasing the damping.

2. Moderate jitter: generally due to media flow conditions. Gases are generally caused by unstable media operating pressures. Regulatory or steady flow devices can be used to overcome or increase instrument air damping.

3. Severe jitter: mainly due to the pulsation of the medium, the pressure is unstable or the pressure, temperature and flow of the gas operating state given by the user do not match the actual state of the instrument, and there is a large difference that causes the instrument to over-range.

Second, the pointer stops at a certain position and does not move

The main reason is that the float is stuck.

Generally, when the instrument is used, the valve is opened too fast, so that the float quickly impacts the stopper upward, causing the stopper to deform and the float to be stuck. However, it is not excluded that the float is stuck due to the difference between the float guide rod and the stop ring. When disposing, the instrument can be removed, the deformed stopper can be removed and shaped, and checked whether it is concentric with the guide rod. If the heart is not correct, the float can be installed, and the float can be pushed by hand, and the float is smooth and unobstructed. Yes, in addition, it must be installed vertically or horizontally when the instrument is installed, and it cannot be tilted. Otherwise, it may easily cause the card table and bring errors to the measurement.

Third, the measurement error is large

1. Installation does not meet the requirements

For vertical installation, the instrument should be vertical and the inclination angle should be no more than 20 degrees.

For horizontal installation of the instrument to maintain the level, the inclination is not more than 20 degrees

There must be no ferromagnetic objects in the 100mm space around the meter.

Install the position away from the valve reducer, pump outlet, process line turn, etc. To maintain the requirements of the 250mm straight pipe section after the first 5D.

2. The large change in density of the liquid medium is also a cause of large errors. Since the instrument is converted according to the density given by the user before the calibration, the flow rate of the water in the calibration state is calibrated. Therefore, if the density of the medium changes greatly, the measurement will cause a large error. The solution can bring the density of the medium after the change into the formula, convert it into the error correction coefficient, and then multiply the flow measured by the flow meter by the coefficient to convert it into the real flow.

3. Since 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 long-term use and pipeline vibration and other factors, the instrument sensing magnet, pointer, counterweight, rotating magnetic steel and other moving parts are loose, resulting in large errors. Solution: You can verify by hand pushing the pointer first. First press the pointer to the RP position to see if the output is 4mA, whether the flow display is 0%, and then verify according to the scale. If the discrepancies are found, the parts can be adjusted. Generally require professional adjustment, otherwise it will cause the position to be lost, need to return to the manufacturer for correction.

Fourth, no current output

1. First look at the wiring is correct.

2. Whether the LCD has a display, if there is no output, there is a bad output tube, and the circuit board needs to be replaced.

3. Lose the calibration value. Due to the failure of the E2PROM, the meter calibration data is lost, and there is no output current, and the current will remain unchanged. Solution: The data recovery operation can be used. If it does not work, the data in the password 2000 can be set first, and then the data in the password 2008 can be set by manually pushing the pointer to calibrate the data from the RP - 100%.

Five, no live display

1. Check that the wiring is correct.

2. Check if the power supply is correct.

3. Reinstall the LCD module and check that the contact is not correct.

4. Check whether the 12 and 13 terminals are connected to the ammeter or short circuit for the multi-wire power supply mode.

Sixth, the on-site LCD always shows 0 or full scale

1. Check the set range and zero point parameters in the 2000 password. ZERO is required to be less than the value of SPAN, and the two values ​​cannot be equal.

2. Check if the sampled data is up. Press the pointer to see the sample value change. If there is no change, the circuit board sampling circuit is faulty and the circuit board needs to be replaced.

Seven, the alarm is incorrect

1. Check the deviation setting d value can not be too large.

2. In the FUN function, the logic function is correct. HA-A represents the upper limit positive logic. LA-A represents the lower bound positive logic.

3. Check the alarm value setting size in the SU.

4. If the LCD bar code indication is correct and the output is not active, check whether the negative pole of the external power supply and the external power supply is connected to the negative pole of the instrument.

5. The circuit board is faulty and the circuit board is replaced.

Eight, the cumulative pulse output is incorrect

1. Check if the alarm value of the selected cumulative pulse output is set to zero.

2. The circuit board is faulty and the circuit board is replaced.