How to determine the quality of a cable
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There is a problem with the pressure signal cable; the measured signal fluctuates. Its insulation has been checked and found to be fine. Are there any other ways to determine the quality of this cable? This post was last edited by marry on 2009-4-1 19:25.]
Signal fluctuations may be caused by electromagnetic interference; check whether the shielding and grounding are in good condition.
It could also be a poor connection. I have encountered situations where loose wiring terminals on the flow transmitter caused large fluctuations in the flow control system, resulting in flow imbalances.
To determine the quality of a cable, it is sufficient to carry out three checks: the first is to check for breaks, that is, whether there is any open circuit, which can be done using a multimeter. The second is shortness, that is, whether there is a short circuit between the cable conductors. Third is the check against the ground; many of us often forget to perform this check, assuming that the cable is fine after checking for short circuits and open circuits. The insulation between the wire core and ground, or between the wire core and the shielding layer, should be checked.
Adding to what was said on floor 4: if there are issues with the quality of the cable, it is possible to encounter the problems mentioned by the original poster. If the cause cannot be identified, try replacing the cable.
Thank you all. I’ll try again to see if I can solve the problem.
If there is no shielding layer, can a spare wire be used as the ground wire?
It probably won’t work; it’s better to use a cable with a shielding layer. In this way, the interference suffered will be very small
Some wires have defective or aged outer coatings, which leads to corrosion inside the wire, an increase in resistance, and interference when the wire is about to corrode and break. It’s best to try using a different wire.
Thanks to the person on floor 9; I also think it’s this issue.
Check using a 500V megohmmeter; the signal circuit should have a resistance of ≥2MΩ