LP Schedule Criteria

An LP may be scheduled for a time in the future. The time may be expressed as either a delta time as an absolute date and time. In either case the command word uses TAI time, which is the standard on-board the SOHO spacecraft. If a delta time is specified, then the delta is from the time that the command is received on-board by the LEB.

Notice however, that the schedule time will be considered as a not-earlier than time. That is, if a previously scheduled LP has not completed, then the new LP will not begin. The new LP will wait until all previously scheduled LPs have completed.

LP Exit Criteria

One of four exit criteria may be selected at the time that the LP is scheduled - cyclic, iteration, exit after an absolute time, exit after a time duration. The first reschedules the LP on a regular basis. The peripheral status request is an example of a cyclic LP. The second counts the number of times the LP is repeated. The last two use time in TAI format. Scheduling by a Delta Time is telling the OBE to schedule the LP at a time offset from the current time. In all cases a full LP would be completed before exiting. Thus if the exit criteria were based on time, the LP would continue to run after time had expired to complete the current cycle. Example 1 - Schedule by Iteration : If the start time 0 , it is assumed that it needs to start now. Word 1 - LSW TAI start time not used = 0 Word 2 - MSW TAI start time not used = 0 Word 3 - exit type Iteration = 2 Word 4 - LSW end time not_used = 0 Word 5 - MSW end time not used = 0 Example 2 - Schedule by Delta Time : If the start time is less than 2 days , it is assumed it is a delta time Word 1 - LSW start time Word 2 - MSW start time Word 3 - exit type ( 3 = END_AT) Word 4 - LSW end time Word 5 - MSW end time