CODEWITHSUNDEEP
anylogic
Shingston
Shingston

Reputation: 217

Agents unable to leave "Conveyor Enter" block. How to wait for "space" on the conveyor before sending agent into flowchart?

In my model, there are pickers moving along a picking aisle. They pick up "Box" agents from a "picking slot", and then transfer those "Box" agents into a conveyor flowchart using the enter.take() method. The specific conveyor and entry point on that conveyor are dynamically defined according to the picker's current location.

A simple flowchart like so:

Conveyor Flowchart

It works most of the time, but when traffic gets high, I end up with the following error.

An agent was not able to leave the port root.enter_convey.out at time 784.505 / date Mar 8, 2021, 12:12:04 AM (current model time is 785.088). Consider increasing capacities and/or throughputs of the subsequent object(s) or using PULL protocol

I suspect it is due to a presentation of the "Box" agent existing within the entry area of the ConveyorPath during the time the following agent is slated to enter. Is that correct? If not, what is the issue?

If my suspicions are correct, how would I go about finding out whether the entry zone of the conveyor I am trying to place agents on is occupied? And how would I go about writing a condition in order to only send agents into the conveying flowchart if the space is free?

EDIT - Additional details, follow up to Yashar's answer:

I have multiple conveyor/picking aisles, and within each of those are multiple pickers.

Let's say picker 1 is dropping off Box X at offset A, and there is currently no space. Box X enters and stays in the queue.

At the same moment, picker 2 is dropping off Box Y at offset B, and there is also no space. Box Y enters and stays in the queue behind Box X.

Now according to the Queue block functions, even if a space frees up at offset B for Box Y, Box Y would still have to wait for Box X to enter the conveyor before it can enter itself. That would not be the behavior I am looking for. Am I correct in my understanding of the Queue block?

Thank you.

Upvotes: 0

Views: 385

Answers (1)

Yashar Ahmadov
Yashar Ahmadov

Reputation: 1636

You can add a queue block after enter_convey. Don't forget to tick the maximum capacity there. If your conveyor system has a maximum number of units it can accommodate, then it is natural that after that limit, no units can enter the system. You can either do that or keep them in the previous station (using a delay block with "stopDelay ()" option) and whenever you have empty space in the conveyor you can send a signal to stop the delay and send it over to the conveyor system.

Upvotes: 1

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