a question about task preempt

Hello
I am facing a case about task preempt. It makes me very confused
the process of the modle i submit in the attachments is:
first "crane6" will do the normal tasksequence passed from "source3" and when its "onload" trigger fired ,i insert a preempt task which i want to let "crane6" be delayed in the UTILIZE state for 30 sec. and then "crane6" goes back to finish the noraml tasksequence.
the problems in my model is :
1. althought the delay task preempts in "crane6" activetasksequence, "crane6" will go on doing the normal tasksequence,and then go back to do the "delay" tasksequence.
2. in the process the model running, system console will appear several exceptions and the activesequence node in "crane6 will contain two tasksequences, i donnot know what is the problem.
what i should do to solve the problems?
Thanks in advance...

Hello,

there might be a conflict in the runtime, if you put a preempting tasksequence in the OnLoad-Trigger. You can instead send a delayed message to the crane and create the preempting tasksequence in the OnMessage-Trigger. That should work.

Jörg

Hi Jörg
thank you for your reply,you're right, the model works rightly. but can you explain why does this conflict in the runtime happen?

Hello,

I don't know, i can only guess. The task you preempt is the tasktype frload. After you preempt, this task will be executed again. Then the OnLoad trigger is executed again. Another delay tasksequence is dispatched. That might the runtime problem. If you send a delayed message, the frload-task is finished and the delaytask is dispatched only once.

Jörg

What I don't understand is why you need a preempting task to make you crane have a utilze task? If it happens all the time you can put it in your tasksequence. If it depends on the situation, use a CALL_SUBTASK.

hi Jörg
thank you! but i find the onload trigger is executed only once for every transport tasksequence. so the delay tasksequence is dispatched only once. the key problem is even the preempt task sequence is in the activesequence node, the crane goes on doing the transport tasksequence,until it finish doing the last task. and then come back to do the preempt tasksequence. i donot know why. at last the activetasksequence node of crane will contain two tasksequence like the picture i submit, and the finished transport tasksequence will never disappear.

hi Steven
thank you for your reply. as you advise, CALL_SUBTASK is good way to solve the problem, but i just want to know what preempt tasksequence can do and what
need to be payed attention to when using it.

I have taken a look at your model and indeed it is very strange. The delay task is in the active tasksequence but is not executed until the normal sequence is finished. I think you should send this to Flexsim. It might be that you found a bug.

I must say that when I open your model I get in a number of places very strange codes like: "¸ù¾ÝÈÎÎñÐòÁÐÓÅÏȼ¶½øÐÐÅÅ� �ò" on the Queue strategy but that might be due to language problems?

hi steven
is the strange codes in the Queue strategy of crane6? if so, yes it is chinese. how to send this bug to flexsim?

At the top of this website you will find Support (between Free Trial and Account) You have to log in to your account and then you can send your model and the description to Flexsim.

The reply to the bug from Flexsim is:
What you are doing is creating a task sequence in the middle of code running. Part of the event of loading the object is to break to travel, since the OnLoad trigger is called before that, it will break away from any task that was created in the OnLoad trigger, including your DELAY task. Commands that aren't new task sequences will work fine.

You can still insert a task in the active tasksequence. It will be then the last task. Move or rerank it right behind the active task. That should work, too.

Jörg