A discussion has begun here about ?grounding? the 0Vdc. I remember this not being a good practice due to possible noise being induced by grounding the 0Vdc to what?s used as the AC ground. DC power supplies have separate outlets for + & - DC as well as a Ground Terminal.
Inside an enclosure you may find AC Power coming in, which in our case is usually 480Vac. You?ll have 3 ungrounded wires and 1 ground, which is landed on a ?ground bus? which is electrically ?earth ground or building steel?. There is usually a DC Power supply (480Vac / 24Vdc) for control voltage; the outputs +24Vdc and -24Vdc (0Vdc) are typically run to their own distribution terminals. The -24Vdc terminals are generally not jumpered to the ?ground bus?.
However, would this be the wrong thing to do?
Most of the DC power is distributed by I/O devices, which provide their own ?ground? terminals. Field devices like Proximity Switches, Transducers, etc terminate to the I/O module; if shield or ground is required the I/O module have a terminal strip for this connection. These I/O modules also have separate connections for +24Vdc and 0Vdc as well as Ground. Again, indicating the 0Vdc and Ground should remain separate.
Inside an enclosure you may find AC Power coming in, which in our case is usually 480Vac. You?ll have 3 ungrounded wires and 1 ground, which is landed on a ?ground bus? which is electrically ?earth ground or building steel?. There is usually a DC Power supply (480Vac / 24Vdc) for control voltage; the outputs +24Vdc and -24Vdc (0Vdc) are typically run to their own distribution terminals. The -24Vdc terminals are generally not jumpered to the ?ground bus?.
However, would this be the wrong thing to do?
Most of the DC power is distributed by I/O devices, which provide their own ?ground? terminals. Field devices like Proximity Switches, Transducers, etc terminate to the I/O module; if shield or ground is required the I/O module have a terminal strip for this connection. These I/O modules also have separate connections for +24Vdc and 0Vdc as well as Ground. Again, indicating the 0Vdc and Ground should remain separate.