Radio Communication interferring with Vibration Transmitters
Radio Communication interferring with Vibration Transmitters
(OP)
Has anyone experienced interference between hand held radios and vibration transmitters installed on rotating equipment?
At our facility, the vibration transmitters installed on several compressors inadvertently go into a state of alarm when exposed to a near radio signal. This causes shutdown of the equipment. What can be the cause and/or solution? I am not familiar with signal processing and interference such as this.
At our facility, the vibration transmitters installed on several compressors inadvertently go into a state of alarm when exposed to a near radio signal. This causes shutdown of the equipment. What can be the cause and/or solution? I am not familiar with signal processing and interference such as this.





RE: Radio Communication interferring with Vibration Transmitters
The cheap (and sometimes effective) solution is to put a small HF capacitor (100 pF - 10 nF) across the transmitter pins and then a small resistor, 10 - 100 ohms*, in series with the two wires. Assuming a two-wire transmitter with 4-20 mA output and floating (no ground connection).
If that doesn't work, you need to ask someone with the right experience and equipment to jave a look at the problem. Many industries have banned transmitters from selected areas, where such problems exist.
*Be careful not to exceed compliance voltage.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Radio Communication interferring with Vibration Transmitters
RE: Radio Communication interferring with Vibration Transmitters
RE: Radio Communication interferring with Vibration Transmitters
The capacitor across the output shunts the HF signal so it gets reduced. But, to do so, there needs to be some impedance in series with it. That is where the resistors come into play. Resistors and capacitor constitute an LP filter that attenuates signals coming from the outside. The resistors also attenuate HF signals entering in common mode so that effects due to parasitic capacitance from active circuitry to ground are minimized.
As I said, this is the first thing to try. If it doesn't work, then get a consultant and have her/him have a go on it.
If the wires are not already shielded, then the suggestion by VE1BLL is worth a try. Shielding can be tricky. Especialy where to ground the shield. Books have been written about that.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Radio Communication interferring with Vibration Transmitters
Another option commonly employed is a big sign:
NO RADIO TRANSMITTERS OR MOBILES TO BE USED IN THIS AREA.