Expression to use to determine Cycle Time and WIP

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oxana9
Posts: 4
Joined: Fri May 16, 2014 10:22 am

Expression to use to determine Cycle Time and WIP

Post by oxana9 » Thu May 22, 2014 10:53 am

Hello Everyone :)

This question has probably been answered before, but i could not find any post making mention. I'm simulating a Value Stream Map. When I do the experiment I add three responses Throughput, Cycle time and WIP.

For Cycle time I used this expression: ModelEntity.TimeInSystem.Average, and for WIP I wrote: ModelEntity.NumberInSystem.Average

However, these two expressions are not working. Does anyone know which could be the correct expression that I can use??

I will appreciate a lot your help.

Thanks.

dsturrock
Simio Team Member
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Re: Expression to use to determine Cycle Time and WIP

Post by dsturrock » Thu May 22, 2014 9:49 pm

The expression you used was close, but this format is used when asking for the data about a specific ModelEntity (e.g. what is the TimeInSystem of ModelEntity[22]).

Instead you want to inquire about the population of all entities. To do that you must use the keyword Population, e.g., ModelEntity.Population.TimeInSystem.Average
Dave Sturrock
VP Operations, Simio LLC

oxana9
Posts: 4
Joined: Fri May 16, 2014 10:22 am

Re: Expression to use to determine Cycle Time and WIP

Post by oxana9 » Thu May 22, 2014 11:02 pm

Thank you for your help. I ran the experiment and now it is working. :)

oxana

oxana9
Posts: 4
Joined: Fri May 16, 2014 10:22 am

Re: Expression to use to determine Cycle Time and WIP

Post by oxana9 » Fri May 30, 2014 1:02 am

Hi, I have again a similar question with the cycle time and WIP. But this time, I will like to know the cycle time and WIP for each machine in my process.

For example, one process is called SrvRipSaw, for the CT I used this expression: SrvRipSaw1.InputBuffer.Contents.AverageTimeWaiting + SrvRipSaw1.ProcessingTime, and for WIP I used this one: SrvRipSaw1.InputBuffer.Contents.AverageNumberWaiting

Can someone help me to see if these expresions are correct or which ones I can use?

Thanks

Oxana

gocken
Posts: 153
Joined: Tue Aug 02, 2011 1:59 pm

Re: Expression to use to determine Cycle Time and WIP

Post by gocken » Sun Jun 01, 2014 8:26 am

As far as I understand, in order the same logic to be utilized you should replace SrvRipSaw1.ProcessingTime expression with Server1.Processing.Contents.AverageTimeWaiting. Note that each time it is referenced the expression SrvRipSaw1.ProcessingTime samples one observation from previously defined expression in ProcessingTime property of SrvRipSaw1 server. On the other hand, Server1.Processing.Contents.AverageTimeWaiting returns the overall average of all processing times that has occured (completed) till at the moment. There seems no poroblem with your WIP expression.

Note: It should be noted that SrvRipSaw1.InputBuffer.Contents.AverageTimeWaiting + Server1.Processing.Contents.AverageTimeWaiting returns "average cycle time" of SrvRipSaw1 server.

oxana9
Posts: 4
Joined: Fri May 16, 2014 10:22 am

Re: Expression to use to determine Cycle Time and WIP

Post by oxana9 » Sun Jun 01, 2014 3:03 pm

Thank you so much for your response and help :)

Oxana

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