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Gripes and Goodies Software problems and suggestions

Old 04-15-2015
Paul Wiedeking
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Default Preempting TS for TE on network with TrafficControl

Hi everybody

I want to model a warehouse system with AGVs switching
different levels via elevator. The warehouse is represented with
network nodes (all levels are connected via a vertical path where I
put the lift). To make AGVs switch levels I use coordinated
task sequences to load/unload them onto the elevator. However,
the network nodes in front of the elevator are connected to a traffic
control. The current traveltask of a TE is preempted (by the coordinated TE)
if the TE arrives at the elevator entry network node.

But this preemptation causes some troubles with the logic of the traffic control.
I also read about this in the help of the traffic control but I didn't find a way
to do it right yet. Any suggestens?

Or is it even better to use a different approach than preempting with coordinated TS
to achieve level switching via elevator?

Old 04-22-2015
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Hello Paul,

I personally have done a similar project in the past and I decided to cut the tasksequence in three parts:

1. From source to node at source level elevator
2. Elevator transport to destination level
3. From elevator node at destination level to destination object.

In the attached sample model you will find part 1 in the Request Transport field of the source, part 2 in OnArrival of NN2, and part 3 in OnMessage of the AGV.

The model is only good for one transport to show you the concept...therefore there is a UserEventConnect, which connects the AGV back to the first NN to be able to run the model again.

There might be other solutions I'd like to see as well.

EDITED: I just noticed, that the lift moves through the AGV. So the first NN needs to be in front of the lift and a coordinated TS might be useful to call the lift, move the AGV into the lift and move the lift to the upper level.

Best wishes

Attached Files
File Type: fsm AGVsUsingElevator.fsm (20.1 KB, 545 views)
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Tom David (05-07-2015)
Old 04-24-2015
Paul Wiedeking
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Hi Ralf,

thank you for in reply.
I think your approach splitting up the task sequence is
pretty nice. It is a little extra code but for me it seems clearer
than interrupting an existing sequence.

I will follow your way.

Thank you very much.


network node, preempting task sequence, traffic control

Thread Thread Starter Forum Replies Last Post
TrafficControl Fernando Igor Q&A 3 09-25-2009 03:09 PM
Questions of TrafficControl ? Li Chin Q&A 0 01-15-2009 07:32 AM
Preempting for machine breakdown Martijn van Oostenbrugge Q&A 4 10-15-2008 01:49 AM
How to dispatch a preempting TS immediately Alexandre Ouellet Q&A 2 07-18-2008 10:20 AM
Queueing preempting task Alexandre Ouellet Q&A 3 05-08-2008 09:22 AM

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