Why are remote level gauges always inaccurate?
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Why is the remote level gauge in my unit always inaccurate? It does not match the instruments indicating on-site.
What type of table? Remote meters need to be calibrated by comparison with on-site meters
Is it because the instrument is too far away from the DCS cabinet, or is it being interfered with by other signal wires?
Could you explain it in more detail? It’s possible to input signals on-site to determine whether it is the on-site indicator or the secondary meter that is inaccurate. 1# 274530245
The liquid level values indicated by on-site instruments and remote transmitted instruments cannot be exactly the same; if the indicated values are identical, then there is indeed a problem. However, the difference should not be too large either.
What kind of level gauge? If it is a double-flange type, is there any fluctuation in the density of the medium being measured, and what is the amount of migration?
It seems to be a double-flange level transmitter; probably the density of the medium inside the equipment is constantly changing, which is why the readings are often inaccurate. If the prohibited values are proportional, then it means the density changes fixedly ； If the prohibited values are equivalent, then it is necessary to change the migration amount. If the equivalent change is proportional, then both migration and density need to be adjusted. If there is a valve, remove it directly to check the migration amount. If there are no valves, we can only collect a few more sets of data and do the calculations.
First, check whether the pressure tapping points for local indicating instruments and remote transmitting instruments are the same. Secondly, pay attention to whether the density of the medium being tested is different from the density used in the calculation range. Finally, check whether the remote reading value always differs from the local indicator by a constant value; if so, it indicates that the zero point is inaccurate. If everything is fine, the only option is to remove the table and verify it again.
It is recommended that the original poster provide more details: what kind of instruments are used, how far the field devices are from the control room, what protocols are employed, and how data is transmitted. This will make it easier for others to assist you
Possible reasons for discrepancies between the readings of remote and local instruments: 1. Different pressure-taking heights of the instruments; 2. Inaccurate range of the remote instrument (usually caused by a difference between the designed and actual specific gravity of the medium); 3. Blockage at the pressure-taking point (partial blockage at this point can cause delays in the instrument’s measurements); 4. The specific gravity of the measured medium is not constant and changes frequently; 5. Errors in the calibration of the remote instrument; 6. Faults in the remote instrument