How to transfer a flowitem from a taskexecuter-team to another taskexecuter-team?

Hi, everyone
I have a system I am modeling, which is composed of the following objects: a source, a team of six transporters, a team of two cranes, another team of four transporters, four processors and a sink.

The system will run in the following sequences:
1. The source generates a flowitem,
2. Select one idle transport from the first transport-team, and use it to bring the flowitem to the unload location,
3. Similar to Step 2, select one idle crane from the crane-team, and let this crane load the flowitem and pass it to another unload location,
4. Select one idle transport from the second transport-team, and this transport picks flowitem to processor.

In Step 2, 3 and 4, there would be a case that a flowitem is transferred from a taskexecuter-team to another taskexecuter-team, which is partly similar to KelvinHo’s scenario (“send a flowitem from a mobile object to another mobile object”), but this model is much complicated. I do not know how to solve this problem.

I know Tom David uses coordinated tasksequences (in “Vehicle to Vehicle Transfer” model) to model a flowitem transfer from a taskexecuter to another taskexecuter, but it seems that this solution doesn’t work in my model. When a proxy task is inserted into a tasksequence, for example, TASKTYPE_UNLODE, the unload station should be specified, but my unload station is not defined/unique, which is one member of a team, thus it couldn’t be specified.

If you know how to transfer a flowitem from a taskexecuter-team to another taskexecuter-team, could you please let me know? I really appreciate your help in advance.

Sounds very interessting, that there will be no unloading/loading station between the two taskexecuter-teams. The real system would be very interessting.
But to your problem:
This way you don´t only need a task sequence for unload/ load the item directly to another taskexecuter, but the information to which. Therefor you need a specific logic, because by using tasksequences you will turn off the most options (for example of picklists) flexim does automatically. Purely is no overview which options you turn off.

I hope the attached model addresses the question.

The code for the coordinated task sequence is on the message trigger of the queue. I didn't spend time making the model look nice so the task executers overlap at the exchange points.

Danny

Danny, thanks for your posting!

I tried to solve this problem by place an additional queue between two TEs(TaskExecuters, including Transporter, Crane, Operator, et al.), and modified the flow as: One member of Transporter team1 -> Queue1 -> One member of Crane team -> Queue2 -> One member of Transporter team2.

I wonder whether this solution can work well in my model, but I am sure that it's not a satisfied solution. Also, it makes my model much complicated by adding so many additional queues in.

New problem emerged from the additional queues.

Because the queue is virtual, the flowitem can't stay in it. In other word, flowitem won't stay in queue even one second, and it will exit immediately after entrance.

Thus I want to set the "staytime" attribute of all queues to zero, but I don't know how to do this.

I really appreciate your help in advance.

You can´t set a maximum staytime in a queue. The item leaves the queue as soon as it can. If you want to set the staytime in queue to zero you have to give the item the way to go. This must be open and not blocked. I think your problem is, that the item stays in queue until the transporter arrives to load it up?

Sebastian,
I am sorry if the description seems to be confused.
I post the model and maybe it will help you to understand the scenario.

In my model, the VirtualQueue1~4 don’t exist in the reality, so I want the flowitems to exit from them immediately after entrance.
Take example for VirtualQueue1, if the crane is not available at this moment or is not dispatched to load the flowitem transferred by Transporter1, the item will not enter VirtualQueue1, and it will stay or be blocked in Transporter1. Once the item enters VirtualQueue1, the crane will load and bring it to next station subsequently.

I´m sorry but can´t have a look into your modell because actually I don´t got any working hardware. Will give it a try on wednesday evening or probably thursday. Hope this doesn´t take to long for you ? It really isn´t possible for me to solve the hardware problem faster.

Ok, I believe I understood what you want to do. Your Crane should unload the Transporter, transport the item and load it to another Transporter anywhere else? This way you have to realize, that the crane and the transporters meet at one location. The loading /unloading szenario wouldn´t be a problem with Task Sequences. But your problem was solved allready.

There is a model of Tom David. Here he realized the loading szenario from one Task Executer to anotherone.
http://www.flexsim.com/community/for...do=file&id=205

Purely I can´t give you more hints, because I still got problems with my hardware. But the model of Tom David will help you. And as I know him, he explained what he has done. This will make it possible for you, to understand how he made it work.
In your first thread I understood the problem another way, that you want a logic behind the task executers where they allways should be called randomly or even if there is anyone free.

Hello Frans,

I have taken a look at your model and have some suggestions that might make it work:

First of all: connect your teams with multiple members to a dispatcher.

Furthermore I would go at it like this:
On the OnCreation Trigger of your source(s) create a task for the dispatcher of the first team. Include the task TASKTYPE_FRLOAD, item, source to pick up the item at the source. Add a second task TASKTYPE_TRAVEL, to travel to the node of your transfer location (i.e. NN4).
On the OnArrival trigger of the pickup location, create a new task for the crane to pick up the item (TASKTYPE_LOAD) and a second task TASKTYPE_TRAVELTOLOC to travel to the second transfer location (i.e. NN5 ).

Create a similar task for the dispatcher of the second team to pick up the item at NN5 and bring it to the Processors. This way you don't need any queues.

Note that if you create a task at the OnCreation trigger of the source without any restrictions, the item will always be picked up from the source. If you don't want that, you have to set some restrictions to pick up the item from the source.

Hope this will help you reach your goal.

Esther

Sebastian and Esther, thanks for your replies, I appreciate them!
I tried to solve my problem by using Coordinated Task Sequences, and it seems to work fine.

Hi, Esther
I have bulit a model accroding to your ideas, and wrote a coordinated task sequence on the OnArrival trigger of one of the pickup location (see NN2 in my model).
Now I wonder why the coordinated ts on the OnArrival trigger of NN2 will never be generated.

I had a look into your model and in the tree.
In Transporter1 are two nodes called tasksequence. I guess they got generated because of bad pointer. Delete these two nodes and have a look. I guess, now it is working.