Problem with pullrequirement and following object

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Enrique Elizaga asked Sep 24, '19 Joerg Vogel answered Oct 1, '19

Problem with pullrequirement and following object

Hi guys,

Hope you are well. In this picking model please follow the picker. I have used a queue that serves as a pallet truck to carry the pallet and cases as a separate object for one reason: when the picker is doing the picking the pallet stays in the aisle independently.

1. I set the logic in on state change. My problem is that if the speed of the model increases, the refresh rate is more spaced and the pallet is put too far from the picking locations. If I run the model in slower speeds, the picker keeps the pallet close.

2. My second problem are locations that are not pulling based on an item. I have colored the location in purple and the problem happens at around 16,500 to 16,900 of the clock. The way i have solved it is buy using moveobject and destroyeventsofobject, for example in the location in yellow right next to the purple one. As you see one is replenished the other is not.

Software Version:

FlexSim 18.2.3

pull pullrequirement ondraw

slotting-propuesta1-v-3.fsm (233.5 KiB)

· 3

tannerp commented · Sep 24, 2019 at 05:45 PM

Hi @Enrique Elizaga,

I wouldn't recommend using the On Draw trigger for having the picker use the truck. Instead, you might consider moving the truck into the picker so that it's always next to him. This would require changing some of your logic a little bit, but it would prevent the queue from being too far away at higher speeds because of the delay in the On Draw trigger.

To help with the second part of your question, could you explain how and when the queues are being replenished?

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Enrique Elizaga tannerp commented · Oct 01, 2019 at 05:04 AM

@Tanner Poulton

The problem with putting the pallet truck inside the picker is that when the picker arrives to the location, he/she should leave the pallet truck on the aisle and goe pick the cases. During the picking activity the pallet truck should not move along with the picker.

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Joerg Vogel commented · Oct 01, 2019 at 07:00 AM

It's devastating. What has this model to do with the second point in the best practices of this answers site?

Post a model that demonstrates your question. The best case is to make a simple model that demonstrates the question or issue

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a-simple-model.jpg (1.9 MiB)

Answer 1 · 2019-10-01T07:57:36Z

Joerg Vogel answered Oct 1, '19

Answer for point 1:

An OnDraw independently approach uses as a final update a delayed message. This is the standard approach for the kinematics, too.

Answer for point 2:

If you know, that you always have to destroy events of an object, then don't let this happen. You run often into this, when you start with a transport tasksequence, that you later change. The command moveobject doesn't replace the events of an unload task. Visually it does the same, but infact the unload task corrects the internal balance of the event states of a transport task. In cases where you want to transport items and you uses a moveobject at one end of the job, please do it on both ends. You use moveobject to load and you use moveobject to unload.

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