Selection Rule

This field applies to the Scheduler only.

During operation processing, if the Scheduler cannot allocate a required resource to a load, it places a request in the resource's request queue. The Sequence Rule controls the sequence in which requests for this resource are placed in the queue.

When a resource becomes available, the Scheduler uses the Selection Rule to determine which requests to allocate next from the request queue. By default, no selection rule is defined. That is, the first request in the request queue is selected when the resource becomes available.

The following rules determine which requests are allocated to loads first from the queue:

When this Rule is Selected...	This Request is Considered First
Sequencing Rule	(No selection rule; use the Sequence Rule. This is the default selection rule.)
Dynamic Sequencing Rule	Use the Sequence Rule dynamically. The request queue is resorted based on the sequencing rule every time the resource removes a request from the queue. This rule works only with the sequencing rules that are based on dynamic and static slack. Static slack is the remaining time to due date. Dynamic slack is the remaining time to due date minus the remaining processing time.
Minimum Setup Time	The request for the load that minimizes the setup time for the next operation in the routing.
Reserve for Job	Requests for loads from the same job the machine is currently set up for, if any such loads exist. If none exist, the Sequence Rule is applied dynamically and the entire list is considered.
First Load	Only the first request ranked by the Sequence Rule. If the first load cannot allocate the resource, do not try the next load in the queue.
Dynamic First Load	Only the first request, applying the Sequence Rule dynamically. If the first load cannot allocate the resource, do not try the next load in the queue. This rule works only with the sequencing rules that are based on dynamic and static slack.
Minimum Setup First Load	Only the first request, applying minimum setup. If the first load cannot allocate the resource, do not try the next load in the queue.
First N Loads	Only the first n requests, where n is specified in Selection Value.
Dynamic First N Loads	Only the first n requests, applying the Sequence Rule dynamically, where n is specified in Selection Value.
Minimum Setup First N Loads	Only the first n requests, applying minimum setup, where n is specified in Selection Value.
Threshold	Apply the Sequence Rule dynamically, and only consider requests with values less than or equal to Selection Value. Note: If the Sequence Rule for the request queue is a "high to low" value type rule (for example, Large Load, High Priority, etc.), consider only requests with values greater than Selection Value.
Tiered Selection Rule	The request is based on the tiered rule selections. The default selection is Sequence Rule.
Priority/Slack/Minimum Setup	The request with the highest load priority. If tied, select the request with the smallest critical dynamic slack. Dynamic slack is critical if it is less than the threshold specified for the resource in Selection Value. If tied, select the request with minimum downstream setup.
Changeover Volume Loads/Minimum Setup	After allocating n loads under the same setup, select the non-zero setup time request. If there are no non-zero setup time requests, zero setup time requests will be selected until the next non-zero setup time load arrives with minimum downstream setup, where n is specified in Selection Value.
Changeover Volume Loads/Longest Wait	After allocating n loads under the same setup, select the non-zero setup time request with the longest waiting time, where n is specified in Selection Value.
Changeover Volume Parts/Minimum Setup	After processing n parts under the same setup, select the non-zero setup time request with minimum downstream setup, where n is specified in Selection Value. If there are no non-zero setup time requests, zero setup time requests will be selected until the next non-zero setup time load arrives.
Changeover Volume Parts/Longest Wait	After processing n parts under the same setup, select the non-zero setup time request with the longest waiting time, where n is specified in Selection Value.
Changeover Processing Time/Minimum Setup	After spending n hours in processing loads under the same setup, where n is specified in Selection Value, select the non-zero setup time request with minimum downstream setup time. Note: Processing time does not include the setup time incurred for the first load.
Changeover Processing Time/Longest Wait	After spending n hours in processing loads under the same setup, where n is specified in Selection Value, select the non-zero setup time request that has been waiting the longest. Note: Processing time does not include the setup time incurred for the first load.
Changeover Elapsed Time/Minimum Setup	After n hours have elapsed under the same setup, where n is specified in Selection Value, select the non-zero setup time request with minimum downstream setup time. Note: Processing time does not include the setup time incurred for the first load.
Changeover Elapsed Time/Longest Wait	After n hours have elapsed under the same setup, where n is specified in Selection Value, select the non-zero setup time request that has been waiting the longest. Note: Processing time does not include the setup time incurred for the first load.
Interrupted/Dynamic Sequencing	Use the sequencing rule dynamically, but put requests for interrupted loads at the front of the request queue. Furthermore, if an interrupted load was being processed by the "selecting" resource, its request is placed at the very front of the queue.
Charge Processing	The request for jobs that consume the Charge material.
User Defined (23-39)	See Writing a Custom Scheduler Rule for more information about creating user-defined rules.

See Using Scheduler Rules for more information about selection rules.