Consecutive Product Skipping Process After “Move Object” in Simulation

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Monte123 asked Apr 9, '25 Monte123 commented Apr 10, '25

Consecutive Product Skipping Process After “Move Object” in Simulation

new-innision-simulering-2_autosave - Copy - Copy_autosave_recovery_autosave.fsm
Hi everyone,

I’m working on a simulation that handles multiple products, each following different routes. I’ve encountered an issue with a specific product type: during one of the processes, I use a “move object” function to direct the product to the correct process. However, in some cases, the subsequent product (the one that enters the system right after) skips its intended process step and instead follows along with the first product. This behavior is particularly noticeable when going through OFM 2 with the first two products.

I’ve tried using zones to solve this problem, but it hasn’t worked so far. Any guidance or suggestions on how to address this would be greatly appreciated.

Thank you in advance for your help!
new-innision-simulering-2_autosave - Copy - Copy_autosave_recovery_autosave.fsm

Software Version:

FlexSim 24.2.1

moveobject zones

new-innision-simulering-2-autosave-copy-copy-autos.fsm (466.0 KiB)

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Lars Jacobsen commented · Apr 10 at 07:11 AM

Please add a screenshot where you highlight the problem area

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Answer 1 · 2025-04-10T07:09:39Z

Felix Möhlmann answered Apr 10, '25 Monte123 commented Apr 10, '25

When the previous batch exits the AOI2 zone, it has not yet vacated the output queue. The movement of the two batches happens in parallel. Because the Wait for Event activity waits for the content to arrive at the target value, it also triggers when the content decreases to that value. So because the first batch is larger than the second, the token is released prematurely while the previous batch is exiting.

There are multiple options of how to fix this: Have the previous batch exit the queue before it exits the zone (which is what I though was your goal). Or change the Wait for Event activity to only trigger when the content increases to the target value. Or use a different entirely, namely the entry of the last item in the batch into the queue.

In you current Process Flow the tokens first have to enter the AOI zones before they exit the OFM zones. Later on they exit the zone as soon as the process finishes though. You should maybe streamline this so the behaviour is always the same (?)

The issue with exiting the previous zone only after a token entered the next one is that the zone needs to "remember" what the previous zone was. I build an example to showcase how this could work. In it I also use a single zone with partitions instead of multiple zone activities. This allows to use the same activity block for each station as a subflow.

batch-processing-1.fsm

In the second version below, the tokens exit the zone as soon as the batch is processed and don't wait until they can move on. This simplifies the logic, but allows the case the multiple different batches can be present in an output queue at the same time (see OutQueue2).

batch-processing-2.fsm

capture1.png (53.8 KiB)

batch-processing-1.fsm (37.9 KiB)

batch-processing-2.fsm (36.9 KiB)

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Monte123 commented · Apr 10 at 03:41 PM

I used the second version in my current simulation, and it worked perfectly! I attached my simulation to show how I integrated it. Next, I plan to continue with the third version you mentioned in another question.

Thank you again Felix for all your help—I really appreciate it!
new-innision-simulering-2_autosave - Copy - Copy_autosave_recovery_autosave.fsm

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