Interference of walkie-talkies on the instrument system
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Recently, the company has encountered several issues involving fluctuations in DCS readings caused by the use of walkie-talkies. Research has shown that using walkie-talkies at close range near safety barriers can cause signal fluctuations; the extent of this impact varies depending on the manufacturer of the safety barrier. Imported brands of safety barriers have a different effect compared to domestic ones； Using a walkie-talkie at a distance of over 1 meter significantly reduces interference ； Used with the cabinet door closed to reduce interference ； Recently, when repairing vibration and displacement instruments related to the shaft system, the use of walkie-talkies near these instruments caused significant interference. Now, warning tapes have been installed and signs have been posted urging people to avoid using walkie-talkies near the instrument panels, in order to prevent fluctuations in the instrument readings that could lead to interlocked shutdowns. The company wants to resolve this issue completely; I would appreciate it if experts in instrumentation could advise on how to deal with such problems
The walkie-talkie pen is right next to the instrument; it’s such a nuisance. Is the pen just idle with nothing to do? Just throw the walkie-talkie away, and that’ll solve the problem. . . Er Dan.
Many years ago, someone came to me to buy a voltage transformer and asked if the intercom would interfere with the C23 voltage transformer in my factory. I don’t have a walkie-talkie. I said that making calls or receiving calls on a mobile phone has no impact on the voltage transformer signal; it doesn’t affect it at all. Typing errors on the pressure transducer occur only when the phone is held close to its casing while making a call; if there is a distance of more than 10 centimeters between them, there is no impact at all. I mean, who would use a phone or walkie-talkie with their face pressed against it? I advised him not to worry about such a ridiculous thing. He said to go buy a walkie-talkie so he could test it. They keep pressing me repeatedly. I thought to myself: Damn it, Nimagbed, how many small voltage regulators do you want to buy? You haven’t bought any yet, and now you want me to buy a pair of walkie-talkies for you to test them with? Who do you think you are? You really are quite smart. {:2_37:} So I said to him: Go and use metal sheeting to make a shielding cover; then you can use the walkie-talkie however you want. But this man doesn’t understand what’s being said; he still presses me to buy a walkie-talkie for him to test it with. The transformer C23 in my village is a highly integrated transformer that operates with pure DC signals; its resistance to electromagnetic interference is excellent. When it comes to electromagnetic interference resistance, even devices like screwdrivers seem mediocre by comparison. Using a 7.5-digit multimeter, I measured the zero-current value of C23 at 4 mA – all 4.0000 digits were stable. It was only at the next decimal place, 0.00001 mA, that I observed brief fluctuations in the reading...... And this fluctuation may not be entirely caused by C23 itself. Even when I disconnected transformer C23, I still saw brief fluctuations in the multimeter’s readings. So I guess the signal stability of C23 might be better. Big bro, I’m very particular about cleanliness; I’m picky about what I eat. I don’t want to do business with people who are despicable and earn money in unethical ways. I told him to go buy it from another place...... {:2_36:}
Meters are low-power DC instruments that belong to the category of low-voltage devices; they are like little sisters who need to be taken care of. Why do you keep using high-power, AC-powered, high-frequency devices to mistreat these little meters? So shameless; I really want to slap you all in the face ........ {:2_36:}.
The correct solution for dealing with that voltage drop is to use a metal box, galvanized pipes, and proper shielding – then there’s no need to worry.
We have not encountered such an issue with DCS, but the use of walkie-talkies does affect compressors (both centrifugal and reciprocating); in those areas, we also have to turn off our walkie-talkies, otherwise abnormal instrument signals can cause the system to shut down.
Such situations do exist; I have encountered them in practice, where walkie-talkies cause interference with on-site vibration probes (accelerometer type), keyboards (used for automatically switching DCS screens), and controllers for high-pressure valves. 1. Interference with on-site equipment: Check that the shielding grounding is in good condition, maintain an appropriate distance when using the equipment, and post signs at the site. 2. Keyboard: The manufacturer will replace the keyboard free of charge. 3. Controller for high-pressure valves: The cabinet doors must not be opened during operation; the walkie-talkie should be kept at a distance of at least 2 meters from the cabinet. It is recommended to check the EMC specifications of the device; if those specifications are not met, contact the manufacturer for a solution (for example, replacing the keyboard resolved the issue of being unable to operate the DCS display). Essentially, this is caused by electromagnetic signal interference, so it is necessary to implement proper signal shielding and maintain a safe distance.
This post was last edited by Nianwang on 2020-1-6 09:19. 1. Check whether the grounding of the equipment and cabinets meets the requirements. 2. Anti-interference type probes are used at the site.