Many of the I/O cards use 24 VDC bussed field power to power their devices. These cards are designed to operate at 21.6 to 26.4 VDC (24 VDC ±10%). To minimize field wiring, you can connect a power source directly to the I/O interface carrier to provide power to field devices that are connected to these cards. It is recommended that the power source is a DeltaV Bulk Power Supply or Legacy Bulk Power Supply. Be sure that the power supply allows the voltage to the carrier to be within the 21.6 to 26.4 VDC range required for the cards that use bussed field power. Some I/O cards use a voltage other than 24 VDC and others do not use bussed field power to power their associated field devices. Refer to the S-series and CHARMs Hardware Reference manual for information on the DeltaV Bulk Power Supplies.
The bussed field power connection on the top of the carrier provides power to the field through the I/O cards only. Extending power from this connection to additional field devices is not supported or appropriate.
If the system requires redundant bulk power supplies or multiple bulk power supplies for load sharing, it is recommended that the DeltaV Bulk Power supplies are used in conjunction with DeltaV Redundancy Modules.