Goods receipt and goods issue through a PI sheet

Can anyone explain to me how the goods issue and goods receipt are done through a PI sheet. What's the logic behind calling the functional module.

Process instructions contain information on:

1. The individual processing steps to be carried out
2. The process data needed for further processing in process management such as process parameter,process data calculation formula,inspection results request etc. During maintenance of PI sheet, the material quantity consumed in each phases and the actual quantity produced are entered (confirmed). Based on the confirmed quantity the system generates GR
for the process order for the finished product and a goods issue for the material withdrawal as soon as the process messages are sent.

Hope this may clear your doubt.

Thanks Arulselvan, if the materials are warehouse managed, how does the goods receipt work, does it work as a normal transaction in the background...

In general scenerio of warehouse management, GR and GI takes in different stages. When you post the GR (both for purchased material and finshed goods) the material stored in entry storage type. Based on the transport order materials are picked and moved to the permanant storage type. This will be taken care by warehouse controller. After entering the material quantity in PI sheet and posting the process messages, transfer request will be generated and the warehouse controller then convert the transfer request into transfer order. Based on the transfer order material will be picked from the permanent storage type and moves to exit storage type and from there material moves to shop floor.I have no experience in this but this is the general procedure.

If this is not working, please reply.