You have not given enough information. This is a complex issue, both from the metallurgical view and the arc physics view. I do not thing there is any "one" valid answer to your question.
In general, you would have to perform a welding procedure qualification test, to find out if your welding parameters produced the desired / required results. If possible, perform a minimum heat input test, and a maximum heat input test, to determine if the parameters you used will get the required Charpy test results with both procedures. Then assume that you can operate somewhere within that parameter and heat input range. However it will still not be ASSURED that some middle range parameter set will produce the desired results!
If you are talking about the welding consumable qualification requirements, the annual test performed by the electrode (electrode / flux combination) manufacturer can be used as a general guide, if the owner only requires "typical" results. In some codes, you are required to have "batch and heat number" manufacturers results. They usually cost a lot of money and require a special order of a whole lot of the electrode
In my own efforts, back in the early 90's, I found that the Charpy results were not necessarily linear in a min/max WPQR series (using the Submerged Arc Welding process). Another thing to be aware of is the % elongation requirement! A WPQR test can produce the required Charpy results and fail the elongation requirements! The size of the electrode and the number of passes also can dramatically influence the mechanical properties results.
Joe Kane