Additional DF-224 Processing

• SIC&DH Interface

  • Communications between DF-224 and NSSC-I is via PITs (Processor Interface Tables)
  • One table goes each way each half second
  • SSM PIT tells NSSC-I about DF-224 and spacecraft

    • Safing directions
    • Spacecraft time
    • Take data flag
    • Maneuver request accepted
    • Maneuver information
    • Guide star information
  • SIC&DH PIT tells DF-224 about SIs

    • Requests V2-V3 offsets
    • Requests STR/SSR start/stop
    • Indicates that a payload safing has been initiated
  • Protocol indicates to each computer that the other is alive

    • DF-224 safes SIC&DH and SIs if it does not receive PIT
    • NSSC-I safes SIs if it does not receive PIT

Previous slide

Next slide

Back to first slide

View graphic version