Pull from List succeeds but token.Work is not assigned

[as5818956]

Hello，I work in flexsim 24.2，I have an issue with Pull From List
I’ve created a logic in my Process Flow that works as follows:

1. Try to pull an AGVWork as token.Work.
2. If successful, proceed with subsequent operations.
3. If not, return to the original position and try pulling an AGVWork again.

Here’s the strange part:

• If the token returns to the original position and then pulls the AGVWork, it works fine.
• If it pulls the AGVWork directly without returning, the pull also succeeds, but later in the flow, token.Work becomes null.

I added some logging to debug this issue.

It looks like the Pull from List succeeded, but the “Assigned To” field wasn’t set correctly.Is there any way to ensure that the pulled object is properly assigned to the token ？

Any suggestions or directions are greatly appreciated.

[moehlmann_fe · Accepted solution]

The token that gets pushed to the list (I'll call it "value token" from here on) enters a Finish activity right after it gets pulled and thus ceases to exist. The logic works in the case where a token is waiting to pull something before a token is pushed to the list. In that case the puller token continues first and the subsequent pull happens before the value token is deleted. If the value token is on the list and then another token enters the Pull from List activity to pull it, the value token continues first, gets deleted, and the error happens.

The error would also occur if the tote pull does not happen immediately but the token has to wait for a tote to become available. The value token would be gone at that point too.

If you pull things that get deleted afterwards, you should add a "Breathe" to make sure it still exists when the puller token continues. Then the puller should copy any labels you need to itself, so you don't rely on the existance of the pulled token at all.

[as5818956]

Thanks