Processing time vs processing holding time

[neto7912]

Hello,

I have a quick question regarding the difference between the 2 metrics I highlighted in the attached picture. I'm done running the model and I'm not getting the results I expected, so I'm trying to go through everything and see where the problem is.

What I wanna know is, what's the average time that this server, DispoToLeave, spent processing (in a busy state) entities?

I really appreciate the help!

[dsturrock]

I understand why this is confusing. I think the main confusion arises because your station has a capacity greater than 1.

The Simio paradigm is that a resource with capacity > 1 is still a single resource with a single Resource State, but just has the ability to process more than one entity at a time. So if any unit of the resource is in use the resource state is busy, if all units are idle the resource state is idle.

With the above paradigm in mind, the ResourceState statistics are not describing individual entity interactions, but rather are describing the transition of the entire resource (all units combined) between those states. The resource enters the Processing (busy) state when 1 or more units become busy. It leaves that state and enters the Starved (Idle) state when all units become idle.

• The average time in spent in that (1 or more units) busy state was 55.5133 minutes per transition.
• This accounted for 6994 minutes total or 69.39% of the time.
• The resource transitioned between the busy and idle states 126 times.

 

By contrast, the Processing (station) statistics are telling you about the entities that enter and leave the processes.

• There were an average of 1.28 entities in the processing station.
• The average entity was "held" (processing) in the Processing station for 25.99 minutes.
• 501 entities were processed.

 

You didn't ask about Capacity utilization, but that also can be tricky to interpret when capacity > 1, especially if the capacity varies over time (which yours apparently does not).

• Perhaps the easiest to understand is UnitsUtilized. This tells you that of the 10 units available an average of 1.289 and a maximum of 8 were in use.
• UnitsScheduled is the same type of statistic, but records how the number of units scheduled to be available varies over time.
• The Scheduled Utilization is the most common statistic telling you basically the ratio of the above numbers. It is a little more complicated than that, but that is beyond this topic.

[neto7912]

Thank you very much for such a clear explanation. And that's good to know about the Capacity Utilization, because I'm using resources that have a capacity that varies over time.