Hi Paul,
I would try to help you with your query.
You need to use LP21 transaction for Replenishment of Fixed Bins (WM).
This would be used to replenish materials from main warehouse to Production supply area.
There would be a seperate storage type for PSA.
Trigger point of this replenishment would be Bin stock situation in PSA. You would be needed to mantain maximum / minimum bin stock in the material master. Once bin stock reaches below minimum stock defined, it would trigger replenishment from main warehouse.
Storage Bin stock would get reduced by goods issue to Production Order which in turn may lead to shortage situation (as defined below) in the bin below minimum stock level.
For LP21, there is a background job which can be established (running every 15 minutes).
Selection variant for LP21
Plant, warehouse number, storage type , put requirement number as "N" and next field as "*".
Execute the background job.
LP21 would look for shortage situation (Bin Stock) and would create a Transfer requirement if shortage exists.
These transfer requirements need to be converted to Transfer Order manually.
Advantages of using Fixed Bin Replenishment :-
1. Automation of replenishment from main warehouse to PSA.
2. Reduction in waiting time for work centers for components.
3. Streamlining of warehouse activities.
4. Biggest advantage of space utilization.
5. Uniform use of bin sizes.
Let me know if you need more information.
BR
Rahul