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About Schedule Horizons and Time Zones

The ABS and Optimizer define the following time periods for scheduling of activities:

• Glued period. A time period, starting from today, when no scheduling of activities is permitted. This period is required to prevent changes to schedules and assignments that are already sent to field service engineers. A glued period is not required; you can set it to 0.
• Contract Scheduling period. The period of time in days for scheduling immediately pending activities for a specific service region. Typically, this period covers days 2 to 8 (starting from the end of the Glued period to a week from today).
• Optimizer horizon. A period of time that includes the Contract Scheduling period. This is the time period within which the Optimizer operates.
• ABS horizon. The period of time in days for scheduling future activities extending from the end of the Optimizer horizon to some time in the future. The ABS horizon is the length of time that is available to book appointments for a service region. Typically, this is from days 8 to 56 (starting a week from now to eight weeks).

Both the ABS and the Optimizer horizons are represented by a single time line (Figure 2), because both are measured from a current time (that is, the time for loading data—see About Loading and Reloading Service Region Data).

Figure 2 shows an example of how these time periods are typically defined. The Glued period is day 1. The Contract Scheduling period is days 2 through 7. The Optimizer horizon, which spans the Contract Scheduling period, is days 2 through 7. The ABS horizon is days 8 through 21, and appointment booking is done for that period of time.

Figure 2. Scheduling Horizons

Activities move from right to left along this time line. For example, a service activity may follow this scenario:

• An appointment to perform an activity is booked into a time slot some time 8 to 15 days from now. The ABS assigns the activity to an employee during the ABS horizon.
• As the days go by, the scheduled activity moves closer to today. On day 8, it moves from the ABS horizon to the Optimizer horizon. In the Optimizer horizon, the Optimizer evaluates the schedule and determines the best time and person to carry out the service activity while trying to minimize the costs of a schedule.
• The activity remains in the Optimizer horizon for 6 days, where the Optimizer may adjust the schedule at regular intervals, at least once each day. This readjustment may be necessary because of changes in personnel, emergency service calls, or service activities that are regulated by contractual commitments (for example, a warranty repair required within 12 hours).
• On day 1, the Glued period begins and the schedule for the activities in a service region is locked.

About Using Long-Range ABS Horizons

You do not need to use the ABS to schedule items that are far into the future, such as six months ahead. This question can arise particularly with companies that schedule preventive maintenance activities months ahead of time. Usually, the ABS is not required because the activities are automatically scheduled when they are loaded into the ABS as soon as they enter the ABS horizon.

For example, assume today is March 1st and the ABS horizon is 14 days. A preventive maintenance activity can be set for May 1st (Earliest Start/Latest Start is May 1st 9 A.M./May 1st 12P.M.). This activity will remain unscheduled until April 17th. When the ABS is reloaded that evening, it queries and finds the activity. Because the activity is unscheduled, the ABS attempts to schedule it automatically using the Earliest Start/Latest Start values.

The only case where you might want to use the ABS to schedule long-range appointments is when you anticipate being so close to capacity that you are concerned about overbooking.

NOTE:  Longer horizons require more memory; also, note the 10,000 query limit on activities for each service region.

Schedule Time Zones

Siebel Field Service stores all times as Greenwich mean time (GMT). For display in the user interface, the application converts GMT to the appropriate local time zone. Service Calendars use Universal Time Code conversions. For more information, see the chapter on ongoing application administration tasks in Applications Administration Guide.

Scheduling uses the following time zones:

• The customer's time zone. Appointments are booked in the customer's time zone, which is assumed to be the same as the service region's time zone.
• The service center's time zone.
• The service region's time zone. Activities displayed in the Gantt chart on the Dispatch Board are in the service region's time zone.
• The employee's (field service engineer's) time zone. Scheduler ignores the employee's time zone and uses the service region time zone.

  CAUTION:  Activity times (for example, Earliest Start and Latest Start) must be specified in the service region time zone. If the dispatcher or service administrator is in a different time zone, you must manually convert to the service region time zone.