Interference issues with remote signals from flow meters
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Problems with signal interference in remote transmission for turbine flowmeters and electromagnetic flowmeters: The manufacturer of these flowmeters is Tianjin Xuner, and the measurement range of the turbine flowmeter is 4–40 t/t； The range of the electromagnetic flowmeter is 3.5~40 t/h. The actual flow rate corresponding to the turbine flow meter is between 0 and 10 t/h ； The actual flow rate corresponding to the electromagnetic flowmeter is 15 t/h. The remote signal from the turbine flowmeter fluctuates greatly, ranging between 3 and 8, while the remote signal from the electromagnetic flowmeter shows no reading. The gauges of the two flow meters show relative stability. What is causing the instability of the remote transmission signal?
It’s probably interference that occurs during transmission; check the wiring
Small signal fluctuations can be removed; for no signal, check one by one according to the manual
The reasons are quite complex and can’t be explained in just a few words
First, verify whether the header output is accurate; if it is, then it’s likely an interference during transmission – check issues related to grounding and shielding.
This post was last edited by Xijiao on 2017-2-21 at 12:46. Personally, I don’t think it’s entirely a matter of interference; based on experience, ordinary interference affects the power supply, and severe interference can cause the LCD screen of the instrument to fail to light up or to become dim. Since electromagnetic flowmeters are usually of the four-wire type, there should be a signal output. Suggested troubleshooting methods: 1. Supply power to the instrument separately, or remove it from the pipeline and power it beside the control cabinet; measure the current output. If the output is normal, check whether the system can be synchronized. 2. Check the pipeline for any changes; for electromagnetic flowmeters, it is necessary to conduct insulation tests on the output terminals, using a megohmmeter to verify that there are no issues with insulation relative to ground, and conductivity should also be tested. Turbines present more difficulties; it might be due to interference issues. It is necessary to check whether there are high-voltage cable trays above, as well as interference from large motors starting nearby. Ensure that the shielding layer is properly grounded, with one end connected to ground. I have encountered similar situations on site. If it is caused by the startup of large equipment in the vicinity, there may be nothing that can be done. It is best to attach a screenshot of the DCS curve for easier analysis. 3. If you need to purchase a gauge, you can turn to me. In case of such issues, you can go to the site; if it can’t be found, it’s due to a problem with my gauge, and it’s my responsibility to fix it. I now want to focus exclusively on after-sales service for gauges. 4. It’s mainly to give me extra points. 5. I also have a lot of practical experience in after-sales support on site: there were cases where the device stopped working properly but functioned normally once it was disassembled; there were instances of interference, fluctuations in the instrument readings, and inaccurate readings. If possible, I’d like to organize this information and share it – I’d appreciate any guidance from those with more experience.