Resource Capacity

Key Concept

Resource capacity is defined by the intervals of time where resources are available to work on jobs as well as how much work can be scheduled on each resource. Resource capacities are determined by a combination of the Resource Properties and the Capacity Intervals. 

Resource Properties

The resource properties dialog can be accessed by double-clicking a resource on the Gantt chart screen:

  • Capacity Type: This field is used to specify if a resource has an infinite or finite capacity and whether the resource is single-tasking or multi-tasking. 
    • Infinite Capacity: The resource can perform any amount of work simultaneously.
    • Single Tasking: The resource can only perform one activity at a time. That activity must be completed before additional work can be done.
    • Multi-Tasking: The resource can perform multiple activities simultaneously based on the resource's Attention Percent. The attention percent is a numerical value for how much of the resource's attention is devoted to that activity.
  • Efficiency Multipliers: These are resource-wide modifiers of both the setup and cycle times that can be changed to reflect whether resources run faster or slower than usual.
    • Setup Time: This value can be changed to reflect whether the setup time of the resource is faster or slower than usual. Values greater than one represent a resource setup that is faster than usual while values less than one represent a resource setup that is slower than usual. 
    • Cycle Time: This value can be changed to reflect whether the run time of the resource is faster or slower than usual. Values greater than one represent a resource that is running faster than usual while values less than one represent a resource that is running slower than usual. 

Capacity Intervals

Capacity intervals can be defined from the capacity interval dialog which can be accessed by right-clicking an existing capacity block on the Gantt, or by going to Settings | Scenario Data | Capacity / Capacity (Recurring) and clicking on "Open".

  • Name: A unique text name to identify the capacity interval, such as "First Shift". This is also used to label the capacity interval on the Gantt.
  • Description: Text that can be used to describe the purpose of the capacity interval, such as "First shift in the assembly department".

Capacity Tab

  • Event Type: Specified the purpose of the capacity interval and determines the impact of the interval on the schedule.
    • Normal Online: Specifies that the resource is available to perform work and that this is a "normal" shift.
    • Overtime: Specifies that the resource is available to perform work and that this is a special "overtime" shift. This type of shift can be set so that additional run costs are applied.
    • Potential Overtime: This is similar to the overtime capacity type. It has no effect on the resource's capacity but provides a visual cue to the scheduler that overtime can be used here if needed. 
    • Offline: Specifies that the resource is not available to perform work. This overrides all other event types previously defined. Jobs can span offline intervals, but no work is performed during that time period.
    • Cleanout: Specifies that the resource is not available to perform work, in cases where maintenance is required. No activities are able to schedule on this type of capacity interval and this overrides all other even types previously defined. Operations that attempt to schedule during any part of this time interval will be pushed to after the cleanout time interval.

Note: If a resource has no capacity intervals specified, it is assumed to be online at all times. In addition, the resource is assumed to be continuously online after the last capacity interval defined so that activities can still be scheduled on the resource. 

  • Timing
    • Start: The beginning of the capacity interval's span. This also serves as the beginning of the recurrence for Recurring Capacity Intervals.
    • End: The end of the capacity interval's span.
    • Duration: The amount of time between the capacity interval's start and end times. For display only.
    • Nbr of People: This is used when a resource is defined as a labor pool resource. This field is used to define the number of people found within this pool.
    • Capacity Hours: This field will multiply the duration by the number of people defined in the field above. If there is one person scheduled to work, then the capacity hours will be the length of the shift duration. If there are 2 people scheduled to work, then the capacity hours will become twice the length of the duration.

Overlapping Capacity Intervals

If capacity intervals overlap on the same resource, then the following rules are applied:

  • Offline intervals will always override other types of intervals. No activities are able to schedule when an offline interval is present.
  • Overlapping normal online and overtime intervals will result in an increase in the total capacity for the overlapping duration. The Nbr of People for each overlapping capacity intervals will be added which will increase the total capacity hours.

Note: It is recommended to avoid having multiple instances of overlapping capacity intervals. If the total resource capacity needs to be increased, it is better to modify the series of intervals to reflect the desired number of people and capacity. 

Recurrence Tab

  • Recurrence Pattern: Unless this option is set to none, the capacity interval will be repeated according to the settings specified. 
    • Skipping: Recurring capacity intervals can be set to skip certain periods of time. For example, if you want to create a capacity interval every other day, you would change the "Skip" field to "1" in the Daily tab.

Note: The duration of the capacity interval can limit the available recurrence pattern options. For example, a capacity interval greater than 24 hours may not be set to have a daily recurrence. 

  • Recurrence End: This determines how long the capacity intervals are applied to the schedule. 
    • End of Planning Horizon: The capacity interval will be repeated until the next interval that would start after the planning horizon. This option is useful when using standard shift patterns that will be used indefinitely. 
    • End After __ Occurences: Capacity intervals are recurring until a specified number have been created. For example, this option could be used to add weekend overtime periods for the next 4 weeks. 
    • End By: Capacity intervals are added until the date specified. This option is useful if the shift schedule is set to change after a known date. The current shift pattern would end at that date and the new one would start, creating a transition between the two patterns. 
  • Short-Term Capacity: If you need to change the number of people in a capacity interval temporarily, you can change that here. Specify the number of people that should be included and how many intervals this change should be applied to. 

Note: Recurring capacity intervals are also called a "series". On the Gantt, recurring and single occurrence capacity intervals can be differentiated by their appearance. Recurring intervals (series) will have diagonal lines throughout the interval block, whereas single occurrences will have a solid background color.