Using a Variable number of Operators for Processing

All,

Here is another model to demonstrate a solution to a specific problem. The problem here is that a process requires at least one operator but can use up to three operators to reduce the process time. We only want to require more operators if they are available at the time.

In this model there are four processors and four operators. The processors have their Use Operator (s) for Process check box checked so that they have to use an operator for the process time. The operators are also required to transport the items from the queue to the processors and from the processors to the sink.

The code that makes this model function is located on the Process Time trigger. In the trigger the code checks to see how many operators are currently available by looking at how many output ports are ready on the dispatcher. The processor then makes sure that the number of operators is at least one but no greater than three. It then sets the "nrofprocessoperators" variable on the processor to the calculated numbe of operators and returns the associated process time.

Because this trigger is fired as a seperate event from the unloading of the item by the operator you don't have to worry about the unloading operator appearing as if they are busy. Also, because this trigger is part of the same event that creates the task sequences for the operators you don't have to worry about another event stealing one of the operators you were counting on away from you.

This is a very easy solution to a seamingly hard problem. I have commented all of the code so that you can read the solution in english instead of trying to interpret code.

Let me know if you have any questions or comments,
Brandon

Brandon have posted many examples with excellent description.
I think these examples with their description should be collected in one place so that we can make better use of them.

Qin Tian,

I'll compile them together and post them in the downloads section on Monday.

Brandon

All,

Rather than putting these models in the downloads section I am putting them here. If someone has a good argument for posting these as individual models in the downloads section please let me know.

Thanks,
Brandon

All,

Here is a message I recieved from James Hayes:

I have a need very similar to your post for Using a Variable number of Operators for Processing. I need to do the same thing except sometimes the processor task get preempted by a higher priority task. At that time, I would like to let the one operator leave and recalculate cycle time based on the fewer operators. In a perfect world, I would like for an operator, once released back from a higher priority task, to have the oportunity to join the process and recalculate cycle time. Do you have any suggestions on where to start? I would post to the forum, but I haven't been approved yet.

Any help you could provide is greatly appreciated.

Thanks,

James Hayes

James,

For a place to start I would suggest looking at Tom David's model at the following location: http://www.flexsim.com/community/for...?do=file&id=84

The model in my thread here does not allow for that and would be hard to modify to do what you are looking for. In Tom's model he does a good job of allowing the process time to be redetermined during the actual process. This will make it easier to modify to do what you are asking.

Let us know how it turns out or if you run into more questions,
Brandon