Sub Tasks

Hi

I have a simple problem regarding sub_tasks. I have an operator that travels to a conveyor to collect a part and calls a sub task to the conveyor, this creates a task sequence for the operator to load a part from the conveyor and take it somewhere.

The problem I have is that sometimes conveyor does not have parts when the operator travels to it and calls the sub_task.

1. To start with I would like to know how to avoid this causing a problem as I currently get an invalid pointer fault as there are no parts in the conveyor, and the model stops.

2. Secondly if possible how can you work round this so that if there are no parts you can get the operator to ignore it and move on to another task sequence and then come back later? For example the piece of equipment supplying the parts may be borken down and you want the operator to carry on working.

Thanks

Anth

If I understand correctly the conveyor creates the tasksequence to pickup a product.

1. In that case simply use an "if" to determine if there is a product on your conveyor. If not, simply don't create the load task but return a 0 or a simple task such as a delaytask with time 0

2. place the call sub task as a first task in your tasksequence and create the whole tasksequence on your conveyor. If there is a part the operator walks to the conveyor and otherwise it just ignores it. Maybe you can even check in the location where you create the tasksequence if a product is available and don't create the tasksequence