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, however, does not include setup and changeover. Batch duration is also used 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 is based on the cleaning regulations. The maximum batch duration can be checked using the Check schedule option after applying certain planning functions. The default value is zero implying that checking is not performed. The maximum batch duration is taken into consideration when creating a process batch with the Create Inflow function. Tank batches are temporarily allowed a longer duration than the maximum value indicated 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 specified when creating a process step. Instead of fixed duration, the rate of the segment can be specified. The rate of a batch segment, batch quantity and duration are related by the rate = quantity / duration formula.

Fixed duration is applicable based on the methods listed in this table. For other methods, the duration and rate are deduced from the upstream and downstream coupled batches.

This table shows the methods and the durations:

Method	Theoretical inflow duration	Theoretical outflow duration
flow process	same as outflow	specify a value
flow buffer	same as outflow	specify a value
batch process	specify a value	specify a value
batch inline	specify a value	deduced
batch buffer	specify a value	specify a value

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

The theoretical outflow duration is specified in the Process Step Entry window for each alternative resource group. The batches are created and 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 specify a rate instead of a fixed duration.

Batches are created within the following duration:

• Fixed duration: The created batch is associated with the fixed duration of the resource group or the resource override. Efficiency does not have impact on fixed duration.
• Rate: The created batch is associated with the rate of the resource group or the resource override, multiplied by the efficiency.

If you modify the resource, the duration follows the process step resource group or resource override for the duration as there is no duration lock. If you lock the resource, schedule process batches do not modify the batch duration, however you can still modify the value manually, thus changing the duration.