When a flow object is busy (in either of the states; working, setup, failed, pause, or unplanned) it will block all variants that try to move on to it. Each such attempt of a variant is stored with a time stap. This is done so that the flow object will know what is waiting and how long it has been waiting to move on to it once the flow object isn't busy anymore. The dispatch setting tells how these waiting variants should be prioritized.
The available options for the dispatch setting are described below.
FIFO (First In First Out) - DEFAULT
The order of the waiting variant is purely determined by the order in which they tried to enter the flow object.
SPT (Shortest Processing Time)
The waiting variants will be ordered according to their average processing time on the flow object they are waiting for (shortest first). Variants with equal average processing time will be ordered according to their waiting time (longest first). In a more compact form the order is determined by the following criterias:
- Shortest average processing time on the flow object.
- Waiting the longest.
SST (Shortest Setup Time)
The waiting variants will be ordered according to their average setup time on the flow object they are waiting for (shortest first). Variants with equal average setup time will be ordered according to their waiting time (longest first). In a more compact form the order is determined by the following criterias:
- Shortest average setup time on the flow object.
- Waiting the longest.
ORDER
The waiting variants will be ordered according to the priority of the first unfulfilled order they are part of, i.e. according to order priority. Orders are managed by the Order logic and prioritized on a first-come-first-serve basis, i.e. the order that have been waiting the longest is given the highest priority. Variants with equal order priority will be ordered according to their waiting time (longest first). In a more compact form the order is determined by the following criterias:
- Longest waiting time for the first order they are part of.
- Waiting the longest.
Note: This dispatching rule is only available for Order replenishers, i.e. flow objects with a connection coming from an Order logic.