Plan Horizon

This field applies only to APS.

Enter the number of days into the future that APS can reserve capacity and resources. Setting a horizon allows you to increase performance by limiting the period of time the system examines when planning. You must enter a value greater than 0.

The plan horizon is used only when the initial pull plan projects a demand to be late (that is, it cannot be planned in the time between the due date and the current date) and the system must switch to push planning. During push planning, the system plans the demand forward from the current date out to an as-soon-as-possible date. If it does not find sufficient capacity and material to plan the demand between the current date and the end of the plan horizon, the demand is displayed as "blocked" and cannot be planned.

It is important to enter an appropriate plan horizon. Too small a setting could result in many blocked demands, while too large a setting could slow system performance. Also, reducing the plan horizon reduces the amount of memory the database server needs to run the planner database.

The Scheduler uses the Days to Schedule parameter, located on the Shop Floor Control Parameters form, to define the time horizon for scheduling demands. One or more of a scheduled job's operations may have dates that are beyond the Days to Schedule horizon. When you run the APS Planning activity, the generated plan will not include those unscheduled operations. To avoid problems with these partially scheduled jobs, we suggest you set the plan horizon to the same time value as the Days to Schedule horizon.