About Duration

Batch duration is the time between the start time (the start of inflow) and the end time (the end of outflow) of the batch. It does not include setup and changeover. Batch duration is used, among other things, to check maximum batch duration.

The maximum batch duration of a resource is the time that a resource can run uninterrupted for one batch. This can depend, for example, on the cleaning regulations. The maximum batch duration can be checked using the function check schedule and after applying certain planning functions. The default value is zero, which implies that no checking takes place. The maximum batch duration is taken into consideration when creating a process batch with the function create inflow. Tank batches are temporarily allowed a longer duration than the maximum signaled in the planning board.

Fixed duration (for an inflow or outflow segment) indicates that a batch has an inflow or outflow duration of fixed length, independent of the quantity of product being made. Fixed duration is entered when creating a process step. Instead of fixed duration, the rate of the segment can be given. A batch segment's rate, batch quantity and duration are related by the formula rate = quantity / duration.

Fixed duration is applicable to the methods in the table below. For other methods, the duration and rate are deduced from the upstream and downstream coupled batches.

 

Method Theoretical Inflow Duration Theoretical Outflow Duration
flow process same as outflow enter value
flow buffer same as outflow enter value
batch process enter value enter value
batch inline enter value deduced
batch buffer enter value enter value

For flow methods, inflow duration and outflow duration are the same.

 

The theoretical outflow duration is entered in the process step entry window for each alternative resource group. When batches are created, they are assigned an outflow duration equal to the theoretical outflow duration of the allocated resource group. The efficiency of the resource group does not affect the duration of the batch. You can enter a rate instead of a fixed duration.

Batches are created with the duration as follows:

  • Fixed duration - The created batch will get the fixed duration of the resource group or the resource override if there is one, efficiency does not play a role.
  • Rate - The created batch will get the rate for the resource group or the resource override if there is one, multiplied by the efficiency.

Since there is no duration lock, if you change the resource, the duration will follow the process step resource group or resource override for the duration. If you lock the resource, then schedule process batches will not change the batch duration, but you can still change it manually and therefor change the duration.

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