Production Order

Hi All,

Please help me to undestand the following scenarion will be grateful.

What are all the basic settings required to create a production order without planned order triggered from sales order.

i.e., Sales order created for a material and a demand need to visible in MD04- while MRP runs it should directly create a production order instead of Planned order.

To set the above set-up, what are all setting I need to set-up in SAP.

Thanks in Advance