Sending items from two conveyors using one elevator to two downstream conveyors

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Amit Kulkarni asked Mar 27, '20 Amit Kulkarni commented Mar 27, '20

Sending items from two conveyors using one elevator to two downstream conveyors

Hello,

In the attached model, pallets are transported on two conveyors to one elevator, which transports them to two conveyors downstream.

Here is what should happen:

1. On Arrival at decision points DP1 and DP2

a. Tokens enter zone
b. Tokens are pushed to list "Ready for Transport"
c. Acquire Resource: Elevator and should travel to pick up level

2. On Arrival at decision points DP5 and DP7

a. Tokens wait for Elevator to be available
b. Tokens enter as a batch into elevator as per load task sequence and get pushed to "Move Elevator" list
c. Elevator waits for batch arrival to execute unload task sequence.

I think the tokens are not pushed on to the list and hence the pallets do not enter the elevator since the batch is not complete. What am I doing wrong?

elevator2conveyors-zones.fsm

Software Version:

FlexSim 20.1.0

Software Version:

FlexSim 20.0.3

list conveyors elevator zones

twoconveyors2elevator-zone.png (152.6 KiB)

elevator2conveyors-zones.fsm (63.0 KiB)

5 |100000

Attachments: Up to 12 attachments (including images) can be used with a maximum of 23.8 MiB each and 47.7 MiB total.

Answer 1 · 2020-03-27T17:30:56Z

Matthew Gillespie answered Mar 27, '20 Amit Kulkarni commented Mar 27, '20

There were a few issues going on here.

First you were using 2 different methods of trying to control the elevator.

In the Move Elevator container you have a token giving tasks to the elevator and pulling from the list to coordinate with items on the conveyor.
You had the items acquiring the elevator and then giving the elevator tasks.

You should choose one or the other, but not both. I updated your model so that only the one token in the Move Elevator container is giving the elevator tasks.

Second, you were correctly using a Zone to limit the items moving up to the elevator, but sometimes 2 items on the same conveyor side would enter the zone before an item on the other side. So I added a partition to the zone so that only one item on each side could enter the zone at a time.

Third, it seemed like you had a lot of extra, unnecessary wait for event and push to list activities. I removed a bunch of activities and got the model working the way I think it's supposed to work.

elevator2conveyors.fsm

elevator2conveyors.fsm (59.5 KiB)

· 1

5 |100000

Attachments: Up to 12 attachments (including images) can be used with a maximum of 23.8 MiB each and 47.7 MiB total.

Amit Kulkarni commented · Mar 27, 2020 at 05:52 PM

@Matthew Gillespie Thank you for the quick response! I understand it now.

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