The queue port is closed when it makes two rounds.

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Ablanco asked Jun 6, '23 Ablanco commented Jun 8, '23

The queue port is closed when it makes two rounds.

I have made a model in which the queue takes from the two shelves some cylinders planned in a table.

I have realised a model in which the queue takes the demand from the two shelves. The demand has been planned in a table that takes 5h.

The queue has been planned to have a maximum of 6 units. When the queue reaches one, 5 more units enter.

The problem is that this process performs well in two rounds of 5 and then the port is closed.

I don't know why the port is closing.

Can you help with this problem?

Thank you very much.

Software Version:

FlexSim 23.1.2

queue ports close and open ports

flexsim-modeloa.fsm (51.1 KiB)

Answer 1 · 2023-06-08T06:33:06Z

Felix Möhlmann answered Jun 8, '23 Ablanco commented Jun 8, '23

After the first batch the input of the queue is actually still open (no red bar in front of the connections indicators). But the individual ports are unavailable (red).

This happens because you open the input multiple times within the On Exit trigger which throws off the port logic.

Opening the input directly in the Exit trigger also leads to timing issues because the last item of the previous batch hasn't actually left the queue at that point. As a result only 4 new items are received.

What you should do instead is send a delayed message to the queue (0s delay) and then open in the input in the message trigger. This makes sure that all other logic has finished when the input is opened.

1686205746255.png (85.9 KiB)

· 1

Ablanco commented · Jun 08, 2023 at 01:23 PM

It may be a viable solution to my problem. I will try as you say.

Thank you for responding to my message.

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