topic Re: Alternate operators are acquired instead of Idle operators in FlexSim Forum

Alternate operators are acquired instead of Idle operators

pinakin_k — Fri, 06 Jul 2018 17:26:58 GMT

[ FlexSim 18.1.1 ]

I have a simple pick and place model, where I am using global table cell as a reference to the count of the operators used. The Resource asset, houses this count.

Every time the operator is acquired, for the same activity second operator is acquired, even if the other operator is idle and standing next to it

Below is the attached model

operator-movement.fsm

Re: Alternate operators are acquired instead of Idle operators

tanner_p — Fri, 06 Jul 2018 17:31:12 GMT

After watching your model run for a bit, I think your model is using the first available operator by default. I'm not sure if this is your question, but are you hoping they would alternate using Process Flow?

Re: Alternate operators are acquired instead of Idle operators

pinakin_k — Fri, 06 Jul 2018 17:41:46 GMT

I don't want to alternate the operators, I want to use the operator that is closest to the process.

Re: Alternate operators are acquired instead of Idle operators

tanner_p — Fri, 06 Jul 2018 18:12:02 GMT

I don't think I quite understand - what determines how close the Operators are to the process? They're on the same node, so it will just pick whichever is easiest, but they're equally close so it will choose the first available.

Re: Alternate operators are acquired instead of Idle operators

regan_blackett — Fri, 06 Jul 2018 18:42:13 GMT

If you give the two operators different colored shirts you will see they are actually alternating because that's how the resource works behind the scenes; the resource that has been waiting to be acquired the longest is the next chosen.

But I agree with Tanner that, choosing the closest one in this case is mostly meaningless since as they finish their travel they are on the same network node so as far as distance is concerned they are equally far away from whatever may call them.

You could do it though using the Acquire activity's Queue Strategy if you really want to.

First go to your Resource's properties and click Advanced, this will give you access to the List interface behind the Resource. Click the '+' button and add an Expression field. Call the Field 'Distance' or some other meaningful name. In the Expression field, put:

distancetotravel(value, model().find("Queue2"))

And click the Dynamic checkbox.

Then in Your Acquire activity, use an ORDER BY Query on Distance ASC, like so:

But again this will just have the default effect in your model since they are always standing with each other, after they each carry one batch of flowitems