Understanding Shielded Control Wires and What They Mean

Shielded control wire is an item that is rarely touched by ordinary people, but it is not unfamiliar to these welders who usually get along with electricity, but we enjoy the shielded control wire that brings everyone cost-effective and convenient.

Ⅰ. Understand the role of shielded control wires and their shielding layers

The shielded control wire is a transmission line that uses a metal mesh braid to wrap the signal line. The braid is generally copper or tinned copper. The shielding layer of the shielding control line can play a certain role of grounding protection. If the cable core wire is damaged, the leaked current can flow into the grounding network along the shielding layer, which plays a role of safety protection. When the current passes through the wire and cable, a magnetic field will be generated around the current. In order not to affect other components inside the wire and cable, we usually add a shielding layer inside the cable sheath to shield this electromagnetic field in the cable.

Ⅱ. The significance of shielding control lines

1. Shielding the control line is to ensure the transmission characteristics of the system in the environment of interference signals. The anti-interference ability here should include two levels, that is, the function of resisting external interference signals and the system itself radiating interference signals ability to work. In theory, a layer of metal composite shielding layer on the surface of cables and connectors can reasonably filter out excess radio waves (this is also the way most shielding system software is used today).

2. How reasonable is the method of shielding the control line? For the shielding system, it is not enough to have a metal shielding layer alone. What is more important is that the intercepting layer must be thoroughly and well grounded device, so that the amount of influencing current can be reasonably introduced into the ground.

However, during actual construction, there are some problems that cannot be ignored in the shielding system. Due to the strict requirements of the shielding layer on the system grounding device, it is easy to cause a poor grounding device, such as excessive resistance of the grounding wire, unbalanced potential difference of the grounding device, etc., which will cause a potential difference between two points in the transmission system , thus causing the current flow on the metal shielding layer, causing the shielding layer to be discontinuous and destroying its consistency.

3. The shielding layer itself has become the highest interference signal, so its performance is not as good as that of the non-shielding system. When the shielded control wire is transmitted at high frequency, both sides must be grounded, which is more likely to form a potential difference on the shielding layer.