There is a good degree of acceptance of standard usage of function keys. These are outlined below.
However, we also note an alternative scheme, which can work with as few as four unshifted function keys. The alternative scheme basically relabels the first four or five keys for each screen. As much consistency as possible is maintained, but there is no strong relationship to key and function. This is a matter of preference and the capabilities of the hardware chosen.
F1 is Save or Post. It should not be displayed unless there is something to save.
F2 is Clear. There is some debate whether this means 'clear the current field' or 'clear the entire screen'. I prefer a compromise clear function. It clears the current field, and if the field is already clear, it shifts back to the previous field and clears it. In this manner, repeated presses of F2 will clear the screen.
F3 is Exit. In general, this means exit to the previous screen, or back to the SAPconsole menu if you are on the initial screen. If there is unsaved data that will be lost, most sites prefer that the user be prompted to save the data.
F4 is Next. This could mean the next peer screen in a series of the same screen, or the next logical screen in a multi-screen sequence. An example of the first usage is the next physical inventory line item. An example of the second is in the bin-to-bin stock transfer, in the transition from the 'from bin' screen to the 'to bin' screen. F4 should not be lit up until data entry is complete on the current screen. Essentially, F4 points to the next operation in a series of related operations to be performed in a single save cycle.
F5 is free for application-dependent use.
F6 is Page Up. This might be in a list (steploop) screen or when stepping through a series of peer screens. It should not be lit up on the first page of a series.
F7 is Page Down. This might also be in a list (steploop) screen or when stepping through a series of peer screens. It should not be lit up on the last page of a series.
F8 is free for application-dependent use and is often used for 'Show List', 'Process' or 'Empty Bin'.
F9 is free for application use.
This usage of function keys complies with SAP standards and is close to standard industry usage. In general, any key that is not ready to be used should be suppressed in the SAPconsole screen 'pushbutton' display, and should also be disabled in the GUI.