How should the PLC cabinet be grounded?
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Do all the electrical components of the cabinet and the UPS’s electrical grounding simply need to be connected directly to the cabinet? The cabinet is welded to the steel channel below. Channel steel is generally used for grounding
Is your channel steel grounded? If the channel steel is connected to the ground, you can do it just like this!
How is electrical grounding handled in ordinary PLC cabinets?
First, the construction drawings should be checked to confirm that the channel steel is indeed connected to the grounding grid； Secondly, after the electrical components are properly connected, it is also necessary to ensure that the ground resistance is less than 3 ohms ； Meeting these two requirements basically confirms that the equipment is properly grounded.
For ordinary PLC cabinets, the electrical grounding can be connected to the electrical protection ground.
In my opinion, the grounding of a PLC should be floating grounding, and it should not be connected to the electrical common ground
Oh, is it usually the channel steel under the PLC cabinet that is connected to the grounding grid? Is this the case for general electrical grounding? Should ground wires be drawn from each PLC cabinet separately to a centralized electrical grounding device?
The grounding of PLC cabinets should be separated from that of instruments and electrical equipment; UPS units are generally not grounded in order to improve reliability. Additionally, generally, the electrical ground resistance should be less than 4 ohms
The shield ground and the protective ground are grounded separately.
It is best to perform grounding separately, especially in the presence of interference sources such as frequency converters.
Generally, the grounding for DCS instruments is separate and cannot be shared with that of electrical systems