Model stops at specified time without error message

[adam_fm]

[ FlexSim 20.1.0 ]

NyFramtidaFlow_Edit3_1.fsm

Hello!

My current model stops after a round of loading & unloading i a "zone". The token stops at a load sequence and, thus stoping the whole model. I´ve tried to look at the event log to troubleshoot why this happens, but i can´t find the reason.

I copied the whole "group" in the processflow from a prevous operation "Group 3", and the whole sequence works from the originated place.

Does anybody got a idea what i´m doing wrong?

Thanks!

[braydn_t]

@Adam FM If you look at the tokens, you are trying to load BatchS5[1], which is null (0x0). You should look where you are assigning the values of that label array, and see why that one might be null.

[matt_long · Accepted solution]

@Adam FM The task sequence error dialog appears because your reference to a flowitem that needs to be loaded is null.

You have a flow on the right side of your Collect & distribute container that continually adds flowitems to a label array but never removes them. Over time those flowitems are destroyed leaving null references on that label. Those null references then get pushed to the List: ItemsInQueue activity. There are a couple of ways to solve this but perhaps the easiest one given your logic, would be to add an Assign Labels before the Run Sub Flow: Pickup RAW-material activity and use the pick option Array>Remove Bad References on the BatchS5 label. This will remove all of those null references so they can't later be pushed to that list.

This doesn't fully fix the issue though. If you repeat random streams and run the model to time 197 then step a couple of times, the first entry on the List: ItemsInQueue has its value set to null. This is caused by the Processing flow. You have a Destroy Object activity that is destroying the flowitem referenced by token.item. In this case that flowitem is Queue4/Product. I'm guessing that's not the flowitem you're intending to destroy.

I hope this helps!

[adam_fm]

Thank you for that elaborate answer @Matt Long and @Braydn T. I appreciate it very much. So i did what you suggested, and then some. A proper dose of spring cleaning you might say. And it worked like a charm!

Nevertheless, i still got a stop in one sequence. This time i checked all the tokens, i tried to check that there wasn´t any "Null" labels, and no nonsense operations in the way etc. But at the end i still came out short with solutions.

If you got time to check out the improved, springcleaned model you will se that "Group SQ1" has some problems in the subflow "Unload finished goods", it stops at unloading. Also, in the 3Dmodel the 3Ditems are hoovering about 20m up in the air when the operator moves the item from the processor to the queue, and from the queue to the stop. Is this related to my problem in some way?

Ps. Please excuse my earlier models apperancel, i see now that the process flow was really, really messy and hard to understand. Also there was alot of functions in the process flow that wasn´t needed!

ProductionFloor.fsm

[adam_fm]

@Matt Long

So i fixed the "non"-issue with the floating items i mentioned in my earlier post, this by deleting the specific operator, and program a new one seems like it was a bug. But i still can´t seem to figure out why it stops after loading 5 items. I realize this isn´t exactly the same reason as for why i first started the thread, but the problem issue still appears, so i thought rather to lock this thread to continue!

[matt_long]

The first thing I notice is all the exceptions showing up in your system console. That's a indication that something is wrong with your logic and needs to be fixed. Nothing should be appearing in the system console if the you want the model to run as intended.

The first exceptions hit were errors Machine Capacity S23 zone that was trying to partition tokens by the label Processor which doesn't exist.

Once you clear those exceptions, running the model produces an exception at the Group SQ1/Unload at FVL/Unload activity. If we look at the system console, the first line states:

exception: FVL No slot was assigned to item

Your operator is trying to unload its items at the FVL rack, but the FVL rack has no available space for the items. You can view the Using 3D Objects > Warehousing in the user manual for more information how the warehousing objects.

For a quick solution I just added more levels to the FVL rack.The rest of the model seems to run fine now. I've attached the fixed model.

productionfloor.fsm

[adam_fm]

Of course! I´ve been staring for too long at the model that i forgot about the actual storage rack. Thank you very much for all the help!

Have a great weekend!

[matt_long]

No problem! Good luck!