About CIP rules

Step

A CIP step is associated with the rule. This step is used to create a CIP batch with the default step quantity.

Rule types

Rule Description
Absolute time

You can use this rule to schedule a CIP batch after the time T when this condition is verified:

The duration T minus the start of a batch that follows the last CIP batch exceeds a specified duration.

Number of batches You can use this rule to schedule a CIP batch after a specified number of batches since the last CIP batch.
Processing time

You can use this rule to schedule a CIP batch when the sum of the process segment durations since the last CIP exceeds a specified duration.

Processing time is used to schedule a CIP batch after the resource has been used for a specified amount of time. Unlike absolute time, processing time does not count the resource's idle time, for example, the time between process batches.

Quantity You can use this rule to schedule a CIP batch when the sum of the batch quantities since the last CIP exceeds a specified quantity.
Transition cost

You can use this rule to schedule a CIP batch when the sum of the transition costs since the last CIP exceeds a quantity.

If the duration or quantity of a batch is not important, but specific events require a CIP batch, you can use a cost matrix for modeling. Each batch contributes to the sum of the transition costs since the last CIP. The contribution of a batch is determined by its changeover cost to the batch that follows it.

The cost of the first batch on a resource is determined by the gauge cost, or zero if no gauge cost is specified. The cost of the last batch on a resource is the transition of its criterion to NONE.

Limits

  • Minimum

    The minimum duration, number, or quantity specifies the minimum number of process batches that must be scheduled after a CIP batch. This constraint can only be used for these rule types:

    • Quantity
    • Processing time
    • Number of batches

    When this constraint is set to zero, it is not used.

  • Maximum

    The maximum duration, number, or quantity specifies the maximum number of process batches that can be scheduled after a CIP batch.

  • Resetting the CIP count for large changeovers

    If large changeovers occur, you might want to always run a CIP operation during these large changeovers. During a large changeover, although the actual CIP batch is not scheduled, the CIP operation is performed in the factory.

    If this option is enabled and a minimum changeover duration is defined, the CIP counter is reset by the solver every time a large changeover occurs, but no CIP batch is scheduled. This option is not available for absolute-time CIP rules.

Gauge

The gauge time and value can be used to specify a start value at a certain point in time for the CIP calculation.

Solver calculations

  • If a CIP rule's gauge date is defined, the solver calculations start from that point in time, using the specified gauge value.
  • If no gauge date is defined, the solver calculations start from the end of the last CIP batch on that resource, using a starting value of 0.
  • If no CIP batch is assigned to the resource, the solver calculations start from the start of the work area.
  • If the CIP rule type is set to Absolute time and no gauge date is defined, the solver calculations start from the start of the first batch after the work area.

Example

A resource's batch count rule specifies that a CIP batch must be placed after every 20 batches. At 9:00 A.M. the CIP batch scheduling for the day starts. At this moment in time, five batches that are not in the planning board have already been processed for this resource. In the planning board, the next CIP batch must be placed after the fifteenth process batch instead of the twentieth. To define these five batches as a start value, you can specify this information:

  • The day's date as the gauge date
  • 9:00 as the gauge time
  • 5 as the gauge batch count

The CIP solver calculations start from 9:00 A.M. onward, using 5 as a start value.

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