Global variable (Two or more conveyors declared as a Treenode Array)

Hello,

I connected conveyors in a row to send objects from point A to B and back.
Then I put these conveyors together as a Global Variable ( Treenode Array).
Now I try to tell this Variable that the maximum content of items in this "area" can only be 1 or 0.
I'm looking forward for some helpful answers.

Thanks

Mats

hi Mats,

You made a guess, now you wish that flexsim behaves as you think it should behave. Your guess is unfortunately wrong.
You can summarize the flowitems that are currently on your conveyors and close or open the input of a conveyor. The command content(obj.) tells you the number of the flowitems or other objects currently in obj.
Another Approach is to count the flowitems entering your defined area and reduce that value by one, if a flowitem leaves the area.

Jörg

Hello Jörg,

thanks for your fast answer.
I can solve the problem for two conveyors with the close and open inputs Trigger option.
My problem is, that I have more than two conveyors in a global variable.
I tried to tell the global variable in FlexScript to close or open all it's inputs, but that is not possible isn't it?

Thanks for your answers...
Mats

I´m quite sure it is possible. But you have to tell every object the command to open / close the port. So there would be needed a "for" loop for example, that sends the information to every involved object.

Maybe you could show more detailed, what you are trying to do. Or post a model, where we can have a look into your work.

Here is an example of my work.
It is simplified, but shows the main point very good.
I only want one item on the four conveyors at the same time.
When the item arrives at the queue the next item can go into the four conveyors.
Thanks for your help ...

Mats

Hello Mats,

you will a face a runtime problem. You must probably controll the order of events in the area with the conveyors. It is done by changing the order of objects in the tree or you will force the events happen in a defined order.
I have attached a model in which a controller defines the input to a area by a message procedure. My model has only two entry points to the four conveyors.
The controller consumes no simulation time but he slows down the model run.

Jörg

Thanks a lot Jörg.
That was very helpful to me.
But I tried to put another conveyor inbetween one gate and entry.
The problem is, that the model stops after the half way.
What do I have to change in the controller to solve that problem?!
Thanks for your answer

Mats

In situations like this I've often found that it is easier to prevent all items from proceeding, and then to chose exactly which item I want to move, rather than relying on port control and event queuing since FIFO is not always desired.

The attached model is similar to Jörg's concept with a central controller, but I use "Do Not Release" in the send to port of the queues and releaseitem() to allow an item to proceed.

Hello Mats,

the area contains with a further conveyor one object more. I have programmed a static amount of objects in the area with the controller. I check in the default case, if the area is empty by a condition
(contentunder(up(current)) < 6) then I open also the second input to the area.
The Container (VisualTool) contains 5 Objects without any flowitems. Now you have 6 Objects and the condition will never be true. Increase the value 6 by one for every object you add in the area. Or better change the condition to
(contentunder(up(current))<=content(up(current)))

Jörg

Thanks so much guys !
Thats the solution of my problem ....