 +_____________________________________________________________________
 ] AUTHOR:            ]                             ] DR:              ]
 ] T. METCALF         ]    PASS PROGRAM NOTE        ]        46513     ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE: SEPT. 1987 ]
 ] LSIS/282-7308      ]      RELEASE NOTE( )        ] REV A: 09/11/95  ]
 ]____________________]_____________________________]__________________]
 ] OI/FLIGHT EFFECTIVITY:        ]  USER AFFECTED:                     ]
 ] REL 19 AND SUBS               ]  CREW (X)  GROUND (X)  DUMP ONLY (X)]
 ]_______________________________]_____________________________________]
 ]        MAJOR SOFTWARE AREA:       ] OPS MODES AFFECTED:             ]
 ]SSW (X)  GNC (X)  VU ( )  SM/PL ( )] 0, G1, G2, G3, G6, G8, G9, S2,  ]
 ]                                   ] S4, P9                          ]
 ]_____________________________________________________________________]
 ] SOFTWARE SUB-AREA: SWITCHES, MDM, HW                                ]
 ]_____________________________________________________________________]
 ] PRINCIPAL FUNCTIONS: SACH                                           ]
 ]_____________________________________________________________________]
 ] TITLE:                                                              ]
 ] MOVING SWITCHES TO "GPC" POSITION AND PASS GPC RECOVERY             ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ] THERE IS A CLASS OF MULTI-POSITION COCKPIT SWITCHES WHICH ARE USED  ]
 ] TO CONTROL SPACECRAFT HARDWARE VIA EITHER THE GPC/MDM PATH OR AN    ]
 ] INDEPENDENT (EXTERNAL TO THE GPC'S) DIRECT HARD-WIRE PATH. THOSE    ]
 ] SWITCHES WHICH FALL INTO THIS CLASS ALL HAVE A SPECIFIED "GPC"      ]
 ] POSITION AS WELL AS SPECIFIC HARDWARE MODING POSITIONS (E.G., "GPC, ]
 ] ON, OFF" OR "GPC, OPEN, CLOSE"). WHEN THE SWITCH IS IN THE "GPC"    ]
 ] POSITION, HARDWARE COMMANDS ARE PLACED IN THE SOFTWARE OUTPUT       ]
 ] BUFFERS AND ISSUED THROUGH THE MDM'S TO THE HARDWARE. OTHERWISE,    ]
 ] THE HARD-WIRE SWITCH CIRCUITS ARE USED TO MODE THE HARDWARE         ]
 ] DIRECTLY, AND NO "KNOWLEDGE" OF THAT HARDWARE MODING CHANGE IS      ]
 ] AVAILABLE TO THE FSW (THE MDM'S CONTINUE TO OUTPUT COMMANDS         ]
 ] CONSISTENT WITH THE GPC OUTPUTS). THEREFORE, IF HARDWARE HAS BEEN   ]
 ] "HARD-WIRE" MODED TO A CONFIGURATION DIFFERENT THAN THAT LAST       ]
 ] COMMANDED BY THE SOFTWARE (USING A "NON-GPC" SWITCH POSITION) VIA   ]
 ] ONE OF THE SWITCHES IN THIS CLASS, AND SUBSEQUENTLY THAT SWITCH IS  ]
 ] PLACED IN THE "GPC" POSITION, THEN THE HARDWARE ASSOCIATED WITH     ]
 ] THAT SWITCH WILL BE CONFIGURED BACK TO THE STATE LAST COMMANDED BY  ]
 ] THE SOFTWARE.                                                       ]
 ]                                                                     ]
 ] THIS OCCURS BECAUSE, PER REQUIREMENTS, THE SOFTWARE COMMANDS        ]
 ] ARE NOT CHANGED TO REFLECT THESE SWITCH POSITIONS. BITE TEST 4      ]
 ] FUNCTION IS TO CARRY FROM OPS TO OPS THE LAST SOFTWARE-ISSUED       ]
 ]                                                                     ]
 ]                - CONTINUED ON SUPPLEMENT PAGE -                     ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]CONCURRENCE:                           ]APPROVAL:                    ]
 ]LSIS:  HUGH D. STOVALL    DATE 02/15/96]                             ]
 ]     -------------------      ---------]                             ]
 ]ASD:   ERIC C. BINGHAM    DATE 02/15/96]                             ]
 ]     -------------------      ---------] DARRELL E. STAMPER 02/20/96 ]
 ]PF MGR: KAYLENE F. KINDT  DATE 02/16/96]------------------- -------- ]
 ]       -----------------      ---------] CHAIRMAN, SASCB      DATE   ]
 ]_____________________________________________________________________]
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 +_____________________________________________________________________
 ]                       SUPPLEMENTAL SHEET                            ]
 ]_____________________________________________________________________]
 ] AUTHOR:            ]                             ] DR:              ]
 ] T. METCALF         ]    PASS PROGRAM NOTE        ]        46513     ]
 ]____________________]                             ]__________________]
 ] ORG/PHONE:         ] OPS NOTE ( )  USER NOTE (X) ] DATE: SEPT. 1987 ]
 ] LSIS/282-7308      ]      RELEASE NOTE( )        ] REV A: 09/11/95  ]
 ]____________________]_____________________________]__________________]
 ] TITLE:                                                              ]
 ] MOVING SWITCHES TO "GPC" POSITION AND PASS GPC RECOVERY             ]
 ]_____________________________________________________________________]
 ] DESCRIPTION:                                                        ]
 ] COMMANDS OUTPUT TO AN MDM BY ANY OF THE FOLLOWING:                  ]
 ]                                                                     ]
 ]  A. SOFTWARE COMPUTED MODING (NORMAL PROCESSING IN ANY OPS)         ]
 ]  B. LAUNCH DATA BUS COMMANDS IN G9                                  ]
 ]  C. ANY G-MEM WHICH HAS WRITTEN COMMANDS INTO THE GN&C OUTPUT       ]
 ]     BUFFER (IN ANY OPS)                                             ]
 ]                                                                     ]
 ] THE FOLLOWING IS AN EXAMPLE OF THE TYPE OF PROBLEM WHICH CAN OCCUR  ]
 ] DUE TO THE HW/SW SWITCH INTERFACE CONFIGURATION:                    ]
 ]                                                                     ]
 ]  THE MPS HE ISOLATION VALVE MAY BE MANUALLY CLOSED USING "NON-GPC,  ]
 ]  HARD-WIRE 'CLOSE'" SWITCH POSITION. THE LAST SOFTWARE-ISSUED       ]
 ]  COMMAND MAY BE AN "OPEN" COMMAND WHICH WILL BE CARRIED FORWARD     ]
 ]  ACCROSS EACH SUBSEQUENT OPS TRANSITION BY BITE TEST 4. WHEN THE    ]
 ]  CONTROL SWITCH IS EVENTUALLY PLACED IN THE "GPC" POSITION, THE     ]
 ]  VALVE WILL BE UNINTENTIONALLY, BUT PREDICTABLY, RE-OPENED.         ]
 ]                                                                     ]
 ] NOTE: MANY COCKPIT SWITCHES HAVE THE POTENTIAL OF CAUSING UNDESIRED ]
 ]  EFFECTS.  CAUTION AGAINST SIMILAR SWITCH USAGE ON THESE TYPES OF   ]
 ]  SWITCHES IS NECESSARY TO AVOID UNPREDICTABLE RESULTS.              ]
 ]                                                                     ]
 ]_____________________________________________________________________]
 ]USER RESPONSE:                                                       ]
 ] A. BE AWARE OF THIS SITUATION AND REALIZE THAT THE USE OF THE       ]
 ]    "GPC" SWITCH POSITIONS WHENEVER POSSIBLE WILL AVOID THESE TYPES  ]
 ]    OF PROBLEMS.                                                     ]
 ]                                                                     ]
 ] B. BEFORE RETURNING ANY SWITCH TO THE "GPC" POSITION, EVALUATE      ]
 ]    THE DESIRABILITY OF PRODUCING A MODING CHANGE TO THAT PARTICULAR ]
 ]    HARDWARE DEVICE. IF HARDWARE MODING IS UNDESIRABLE, VERIFY THE   ]
 ]    SOFTWARE OUTPUT COMMAND STATUS TO THAT DEVICE. MAKE THE FINAL    ]
 ]    DECISION TO PLACE THE SWITCH IN THE "GPC" POSITION BASED ON THE  ]
 ]    ACCEPTABILITY ON THE EFFECTS ANTICIPATED.                        ]
 ]                                                                     ]
 ] C. RECOGNIZE THE POTENTIAL EFFECTS OF BITE TEST 4 IF PASS GPC       ]
 ]    RECOVERY ACTIVITIES ARE PERFORMED.                               ]
 ]_____________________________________________________________________]
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