Regarding the issue of signal line shielding
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Dear experts, when should the shielding mesh of a signal cable with shielding be grounded at both ends? What about cables with double shielding layers? There are several pairs of wires in the cable; each pair is wrapped in a copper mesh, and the outermost layer also consists of a copper mesh that covers all these wire pairs. Should the outermost shielding mesh be grounded at both ends, or should the shielding meshes of each internal wire pair be connected together and grounded at one end only?
The two layers of shielding serve different purposes in preventing interference signals: single-ended grounding is mainly used to prevent static electricity, while grounding both ends of the outer layer is primarily intended to avoid interference from electromagnetic signals and similar ones!
Do alternating current flow lines constitute electromagnetic interference? Does single-ended grounding have an effect on interference in alternating current cables?
May I ask if all double-layer shielding nets are single-ended grounded?
Let me, this fake expert in the field of instruments, explain it to you. 1. Why can’t it be grounded at both ends? Because the potentials might differ, which would cause current to flow in the shielding wire; wouldn’t that instead increase interference? ； 2. Both layers of shielding require single-ended grounding ； 3. The function of the shielding layer is primarily to suppress electrostatic interference, not magnetic field interference; if there is indeed magnetic field interference, shielding and grounding will not solve the problem.
The shielding is single-endedly grounded on the DCS side; grounding at both ends would create a potential difference, resulting in a weak current
Low-voltage AC power generates almost no electromagnetic interference; high-voltage AC should also produce little interference. It is variable-frequency cables that tend to cause magnetic field interference, while power-frequency electromagnetic interference should be minimal. Moreover, the three wires of the cable are arranged in a triangular pattern, which allows them to cancel out magnetic field interference among themselves.
Shield wires are all single-sidedly grounded to prevent the formation of potential differences. Some cables consist of a main screen and sub-screens, but they still need to be grounded together on one side; generally, grounding is done on the cabinet side, while the shielding layer on the field side must be properly covered to prevent accidental grounding.
Should the main screen and split screens be grounded at a single point together?