question

I just had to do this on a model this week. I chose to do the whole operation on the conveyor. Here's a small video of it in action. You'll notice there's a station and decision point on top of each other (it could be two stations but it was easier to see this way). That's because there are two conveyors. One going left to right and one going right to left.

A board comes in from the right and stops at a decision point. The pallet comes in from the left and stops at the station. Once the pallet arrives, it is raised up 3" and then the board is released and stops under the pallet. The pallet then lowers 2.25" and then resumes.

Here's what the process flow looks like. I'm not able to share any of the model, but here's a step by step of what I'm doing.

The only logic in hte 3D that I have is the Station has an OnMessage trigger with two Translate Item pick options. One to lift and one to lower. I did have to copy these from the On Arrival trigger since they aren't available in On Message. And I inserted this line below the code header.

Conveyor.Item conveyorItem = conveyor.itemData[tonode(msgparam1)];

I passed the pallet flowitem into msgparam1 using tonum(token.Pallet).

The process flow is broken down into two sides and two resources (or zones could have been used as well, personal preference). On the left side is the logic for the pallet. We wait for the pallet to arrive at the first decision point, then kick off a token with a reference to the item. The token then waits for the pallet to arrive at the load station (if an item is already there the conveyor will stop the item). Once it arrives, it stops the pallet and lifts it up. This is where I send the message.

On the right side, a similar thing happens. The token is kicked off when the pallet arrives at a decision point off screen. It then stops the board at the decision point at the right side of the image.

I use a synchronize to cause the tokens to wait for which ever token hasn't arrived yet. That way if the board arrives first, it will sit and wait until there is a pallet to load. And vice versa, if the pallet arrives first it will wait for a board.

Next, the board will resume and move underneath the pallet. I stop the board once it arrives at the middle decision point.

Again, another synchronize to keep the tokens from progressing without each other.

Next I lower the pallet, and then another synchronize.

Finally, I change the shape frame of the pallet flowitem to be one that has a board at the bottom. This made things easier than trying to load another flowitem into the other, although you could definitely do this. I resume the pallet and release the area for the next pallet to enter.

At the same time, I destroy the board and release the area for the next board to enter.