Applies To:
  • CitectSCADA Batch Versions

How much load will the Batch Engine impose on the CPU? 

The Batch Engine spends almost all its time evaluating Transitions. Most Transitions read one Parameter/Tag (sometimes a few Parameters/Tags) from Citect to be used when evaluating Transition expressions. Even with a large number of simultaneous Batches running, this may not impose a high load on the CPU.

The other time that there is activity in the Batch Engine is when a Phase is initiated. At this time, Parameter values are written to Citect Tags and Reporting values are read from Tags and are stored in the Batch MSDE database. Usually only one Phase is triggered on a Batch Engine cycle and the number of Tags is typically between 0 and 10. Occasionally a few Phases will be triggered simultaneously, at the start of a simultaneous path or just by coincidence. For the majority of Batch Engine cycles there will be no Phase activity at all.

Of course, the load actually imposed on the CPU varies from project to project. When you view activity for a Batch in the Batch Scheduler you should be able to confirm that most of the time is spent in Transitions (marked by "(T)"). The only time that the Batch Engine should be waiting on a Phase is if it is waiting for a Pipe to be released by another Batch.

If a Batch is found to be waiting on a Phase and this is not the reason, there is a problem.

Some possible causes are:

1. A Material required by a Batch cannot be found in a Tank

2. The Tank in which a Material can be found is inactive

3. An invalid Parameter Tag has been configured

4. A Tag has been assigned to a Release Parameter