Knowledge

Relationships & Logic

Calendar Used for Relationship Lag

Lag calendar option: pred / succ / 24-hour / project; default Successor

P6 Predecessors tab. FS relationships with lag 0.
Lag is on the relationship row. Lag calendar is which calendar those days use.

Lag lives on TASKPRED as lag_hr_cnt (hours). Which calendar consumes those hours is a schedule option, not a per-relationship field.

Option names (Oracle schedule options)

EPPM Settings tab and Professional Schedule Options both list:

  • Predecessor Activity Calendar — lag from the predecessor's calendar
  • Successor Activity Calendar — lag from the successor's calendar
  • 24 hour Calendar — 7 days/week, 24 hours/day (continuous work periods)
  • Project Default Calendar — the calendar marked Default for New Activities (Project Details, Defaults tab)

XER column (Oracle SCHEDOPTIONS map): sched_calendar_on_relationship_lag. Stored values are not listed. Unverified. Do not invent codes.

Default

Professional Schedule Options: "If you do not select a calendar, Successor Activity Calendar is used to calculate lag."

EPPM web-services RelationshipLagCalendar: same four strings; "If you do not select a calendar, the successor activity calendar is used."

Treat Successor as the documented default when the option is unset. Whether a given XER always materializes that default into sched_calendar_on_relationship_lag is unverified.

Unit conversion (separate from the lag calendar)

Oracle (both EPPM and Professional): lag entered in a unit other than hours is converted to hours using the predecessor activity's calendar. That conversion rule is not the same setting as "Calendar for scheduling Relationship Lag."

SS lag when the predecessor starts out of sequence is a different option (Early Start vs Actual Start). See Retained Logic vs Progress Override vs Actual Dates and p6/taskpred.md.

Sources

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