The DeltaV system provides initialization, diagnostics, and run-time monitoring for a fieldbus segment. Depending on the control strategy, the DeltaV system either executes the control algorithm or, if control resides in the fieldbus devices, displays the ongoing parameters. The H1 card or the H1 with Integrated Power card is the starting point for the communications on a fieldbus segment.
The H1 or the H1 with Integrated Power card is the only primary Link Master allowed on the fieldbus segment. The DeltaV system supports one backup Link Master device on each fieldbus segment.
The H1 card and the H1 with Integrated Power card reports its operating mode (simplex or redundant) to the DeltaV controller based on the type of terminal block on which it is installed. When a redundant pair (an active and a standby card) is installed on a redundant terminal block, it reports itself as operating in redundant mode. When a single card is installed on a terminal block, it reports itself as operating in simplex mode.
For redundant applications, the redundant H1 and redundant H1 with Integrated Power cards ensure uninterrupted communications between a fieldbus segment and the DeltaV system. For applications requiring protection such as high availability applications, redundant H1 cards can be used in conjunction with redundant power and short circuit protection.
The H1 card requires 12 mA of fieldbus power in simplex mode and an additional 12 mA of fieldbus power (24 mA total) in redundant mode. Be sure to account for the additional power requirements in your segment design. The H1 card requires a terminator at each end of the segment.
The H1 with Integrated Power card provides up to 400 mA of fieldbus power for each of the two segments. The integrated power supply is powered from a 24 VDC bulk power supply that is connected to the S-series 8-wide carrier. The H1 with Integrated Power card contains an integrated terminator for each segment; a second terminator is required at the field end.
The S-series and CHARMs Hardware Reference manual contains specifications and wiring diagrams for the H1 and H1 with Integrated Power cards and the terminal blocks used with these cards.