Specs to go out.pdf

This is a preliminary design document that defines the IOC Heartbeat Message interface format for the Henschel Input/Output Controller (IOC) system on the USS Stennis (CVN-74), prepared by L-3 Communications-Henschel in October 2004. The document specifies the format for heartbeat status messages transmitted by the IOC, which follows the Navy SMF&P format and includes an extended status data header.

The document details the message structure, including packet headers, data headers, and checksums, with specific bit-level formatting requirements. Key components include status data structures containing three status words, two temperature probe values, and a 40-character source ID string. The status bits monitor various conditions including NAVSSI data status, BFTT data presence, IRIG-B synchronization, latency correction, temperature parameters, hardware faults, and UPS status. The message format uses Big Endian formatting and includes provisions for unique message identification through an incrementing counter system for messages between the Henschel NavConverter and MCS.