Introduction
Remember that the Resources themselves have been assigned Capabilities, tasks or functions that those Resources are able to perform. In order for an Activity to be scheduled, however, the individual Operations must also reference both the number of Resources required as well as the Capabilities those Resources must have.
Key Concepts
Primary and Helper Resource Requirements
An Operation can specify one or more Resource Requirements — one for every Resource that is needed to perform the Operation. If an Operation, for example, requires a CNC machine and a CNC operator then the Operation would have two Resource Requirements — one specifying a Capability such as CNC and one specifying a Capability such as CNC-Operator.
Every Operation has exactly one Primary Resource Requirement. This is the one that determines the duration of each of the portions of an Activity (Setup, Run, and Post Processing). If an Activity is scheduled across an offline time then the duration of the Activity is lengthened to account for that inactivity. If an Operation has multiple Resource Requirements then the non-Primary Requirements are considered to be Helper Resource Requirements. The main difference is that these do not determine the duration of the Activity, they are scheduled according to the times on the Primary Resource. They must be available during the entire duration of the Activity as specified by the Primary Resource Requirement.
Typically if multiple Resources are required for an Operation, the labor defines the Primary Requirement since people have Capacity Intervals indicating their work hours. A machine could therefore be defined as a Helper Requirement since it is available continuously or usually at least more continuously than are people. However, if the machine will determine the length of the Activity (for example if using sequence-dependent setup) then the Primary Resource must be the machine since only the Primary Resource determines the Activity duration.
Required Capability
A Resource Requirement determines the number of Resources that an Operation needs in order to run. From example above, we may need a CNC machine and a CNC operator, which are the Resource Requirements — we need two Resources. The specific capability of “CNC” and “CNC-Operator,” however, are called the Required Capability. It may be helpful to think of the Resource Requirement as comprising of two parts: 1) the number of machines and 2) the capability that is required.
APS will refer to the Capability Assignments in order to correctly schedule the activities to both the correct number of resources as well as to the correct resources. The difference is subtle but important. For example, if only one Resource Requirement is set, but two Capabilities are required, APS will attempt to match the Activity to a single Resource that has both Capabilities. In our previous example, it would require either a CNC with the capability “CNC” as well as “CNC-Operator” — essentially the CNC would have to be able to operate itself.