Can the signal cable from MCC to DCS run in the instrument tray?
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As titled: Can the signal cable from the MCC inverter to the DCS use the instrument tray (including DI/DO/AI/AO)?
Although many design firms do this these days, based on my past experience, the DO points must never be placed on the same frame; otherwise, interference signals can cause a lot of problems. In a typical DO circuit, there is an AC 220 voltage signal, which acts as a source of interference; any issue with shielding can lead to various types of interference.
It is possible to use the instrument tray. But if possible, it is best to lay it separately. MCC generates strong interference, and the interference from some models is in the form of square waves, making it very difficult to eliminate. If they must be used together, proper shielding and grounding are essential.
If possible, it’s best to lay additional cables; DO is generally 220 AC, while the others are fine
If possible, it’s still better to lay them separately! I used to think it didn’t matter either, but once I accidentally tried to measure the induced voltage, and it was as high as 90V. It’s quite scary to think about if this were placed alongside the instruments on the compressor’s shaft!