Picking HUs Manually (Process Order) 
Use
For the production supply, you can pick ingredients manually in
handling units (HUs). This includes:Picking is carried out using the reservation items of the process order.
Procedure
The Picking for Production Order screen appears.
Enter the following:
You can check which materials are assigned to the process order but not yet picked on the Open Reservations tab page.

Operation column:
A material can be assigned to an operation or phase in the master recipe to ensure correct sequencing during production. If a material is not assigned to a phase, the system automatically assigns to the first phase of the process order. During picking, the material can be:

The HU number can be assigned independently if an external number range assignment has been maintained in Customizing. The HU number must then correspond to this number range.
The PI sheet appears.
The system confirms that picking was successfully carried out with y (yes).
If picking was not successfully carried out, an error message appears.
The picking data is transferred to the batch record. You can use the message monitor to check whether the messages have been processed correctly. This is necessary if the system does not send the messages automatically.
For more information, see
R/3 Integration Using Process Messages
Manual picking can be called up again after completion.
It is a good idea to pick parts of the materials at different times during production. For example, the materials for the first phase(s) can be completely picked, and the rest of the materials can be partially picked.