Good evening every one,
The MOV instrument has 2DI and 2DO command to the PCP panel. the I/O rack of DI and DO for panel is different. Can I use 4C or 2 Pair cable for this command? Kindly suggest solution with your experience.
Since both the DI and DO are control signals they can be in the same cable if the voltages are the same.
So you could use 8C cable from the marshaling to the field or a larger home run cable from marshaling to a local JB then a 8C cable to the MOV.
There is no local JB. Instrument directly connected from field to PCP. There is only 4 Commands. And Why 8C cable is needed? can you please explain sir?
4 commands. 1 command is 1 pair is 2c. Al of equal voltage (24VDC ?). 8C cable. Perhaps 10C to use number 9 for grounding.
Take in account the diameter of the cable, cable entry dimensions of MOV. You might have to split up 2x 4c cable.
Hence local junction box. One thick cable to junction box, split up in thinner cables to instrument.
2C for each DI and DO.
I do not know your working voltages (I/O or MOV), cable lengths, cable gauge or circuit loads, but if the MOV has some internal commons you may be able to reduce wire count to 3C for 2 DI and 3C for 2 DO. You will have to consider I/O voltage vs MOV control voltage, i.e. 120VAC or 24VDC, and what isolation is required between I/O and MOV control circuit.
Do you have interposing relays between both DO and DI and field? Are isolating relays in I/O cabinets, marshaling or MOV?
Depending on your I/O types, isolation and fusing you may not want to share voltage sources or commons between DI and DO.