Capacity resources are special resource types that are unlike human or technical resources in that their capacity may be increased or reduced by carrying out functions. They can also be used in the control flow to decide which path of a branch a process folder is to pass according to the current capacity.
Alternative or additive allocation of resources
Capacity resources that have been allocated to a function using is consumed by and is used by connections are used additively, that is, all allocated resources are required in order to carry out the function. The allocation strategy can be changed using the function's Resource allocation attribute. Select Alternative or Additive.
Controlling the capacity of capacity resources
The initial capacity of capacity resources is indicated by the value of the Startup capacity resource attribute. If this attribute has not been specified, 0 is added for the Current capacity attribute as soon as the simulation is started. There are three ways to change the capacity of a capacity resource: it can be permanently increased, permanently reduced or temporarily reduced while the function is being carried out.
Permanent increase of the capacity of capacity resources
The capacity of a capacity resource is increased if it is linked to a function via a produces connection and the function is carried out. You can control the quantity by which it is increased using the Quantity connection attribute of the Simulation attribute type group. If the Quantity attribute has not been specified, the capacity of the resource is not increased when the function is carried out. The function is not carried out if this causes the capacity of the resource to increase above the value specified in the Maximum capacity attribute.
Permanent reduction of the capacity of capacity resources
The capacity of a capacity resource is reduced if it is linked to a function via the is consumed by connection and the function is carried out. You can control the quantity by which it is reduced using the Quantity connection attribute of the Simulation attribute type group. If the Quantity attribute has not been specified, the capacity of the resource is not reduced when the function is carried out. The function is not carried out if this causes the capacity of the resource to fall below the value specified in the Minimum capacity attribute.
Temporary reduction of the capacity of capacity resources
The capacity of a capacity resource is temporarily reduced if it is linked to a function via the is used by connection. You can control the quantity by which it is reduced using the Quantity connection attribute of the Simulation attribute type group. This reduction is only effective while the function is being carried out. Once the execution of the function is complete, the original capacity quantity is available again. The function is not carried out if this causes the capacity of the resource to fall below the value specified in the Minimum capacity attribute.
The checks performed to ensure that the maximum and minimum capacities are observed work with provisional values. The quantity is increased/reduced only after the function has been carried out. However, the function reports the provisional capacity quantity as soon as the execution starts. The functions that are carried out after this function also use this provisional value as the basis for their calculations. This prevents the capacity from exceeding or falling below the maximum and minimum values when functions that cause capacities to change are carried out in parallel.
Guiding of process folders with one capacity resource
The behavior of an XOR or OR rule can be controlled by specifying probabilities. To decide which path a process folder should take, the capacity of a capacity resource can also be compared to a fixed value when a rule is activated. The branch must be followed immediately by an event in each path. Each event must be linked to the capacity resource via an is compared to connection. The Comparison operator and Comparison value (numeric) attributes must have been specified for each event. The comparison value is the defined capacity value of the resource. This value is compared to the comparison operator, which defines how to perform the comparison (>=/<=).
At an OR rule, a specific event is activated after the branch. A process folder is forwarded to the next control object if the result of the comparison between the Current capacity and Comparison value (numeric) attributes using the comparison operator is True. If the conditions have not been entirely specified, the process folder waits at the rule.
Forwarding based on resources takes precedence over forwarding based on ERM attributes or probabilities.
Guiding of process folders with two capacity resources
When process folders are guided using a single capacity resource, the capacity of a resource is compared to a fixed value to decide whether the process folder should be guided along a specific path. Besides this option, the current capacities of two resources can be compared. The process folder is then forwarded in accordance with the result of this comparison. The branch must be followed immediately by an event in each path. Each event must be linked to the capacity resource via an is compared to connection. The Operand position attribute of both connections must have been specified and must have different values. The Comparison operator attribute must have been specified for each event.
At an OR rule, a specific event is activated after the branch. A process folder is forwarded to the next control object if the result of the current capacity comparison of the two resources is true, taking into account the comparison operator. The value on the left of the operator is taken from the resource with the lower Operand position attribute value, the value on the right is taken from the resource with the higher value for this attribute. If the conditions have not been entirely specified, the process folder waits at the rule.
Forwarding based on resources takes precedence over forwarding based on ERM attributes or probabilities.