Change the active Task

Hi,

We have build a storage area, in that flow items can be placed and stacked. A crane is dedicated to transport flow items in and from the area. The crane receives transport requests by the "use transport"-field.

Now, when the crane is ready to do a task sequence, it may be, that the transport can not be done, because another flow item is stacked at to top of the item to move. So, the crane has to move the other object away at first. However, this situation is only clear just bevor the task sequence starts and not at the time the task sequence was created, i.e. over-writting of a passto-Event does not do the job.

We want to check the situation just bevor the task sequence begins and if necessary, change the task sequence. Is there a way in Flexsim to do this?

One possible way of doing this is to modify the task sequence by inserting a CALLSUBTASKS task before the load task for the target item. When the CALLSUBTASKS is executed, you check to see if there is a blocking item and if there is you dispatch the tasks required to move it. Check the CALLSUBTASKS section of the user manual for a good explaination of how to do this.

DAnny

Yes, this is a good idea. We found another (simple) solution as well: The transport request is transformed into a single sendmessage task that contains all transport parameters (source, target, item). The message trigger of the crane receives the message at the right time, decide what to do and creates a corresponding task sequence with a very high priority value.

Thank you!