HP 54710A User's Reference Manual page 167

Messages
Control setting is unchanged: Entry was not completed
The enter key was not pressed after typing in numbers using the keypad
before changing menus. If the entry still desired, it will have to be completely
entered again.
Execution not possible: ? has no acquisition capability
The plug-in indicated by the ? does not have acquisition capability. Select
another plug-in that does have acquisition capability. For example, the HP
54718A plug-in only has triggering capability.
Function cannot be performed on the selected waveform
The function is not defined for this waveform type, and, thus, cannot be
performed.
Id error occurred in plug-in ?: Service is required
The information the mainframe downloaded from the plug-in's memory is
inconsistent with the plug-in's hardware. The ? indicates which plug-in has
the Id error. This is a special case of memory error. Check the following:
Reinstall the plug-in.
Finger tighten the knurled screw on the front-panel of the plug-in.
If these actions do not solve the problem, there must be a hardware problem
in mainframe or plug-in. Call Hewlett-Packard service.
Incompatible setup
It is possible that due to a system firmware change, a previously saved setup
may become incompatible.
Low battery voltage detected: Service is required
Change the battery as soon as this message is displayed. Cal factors and data
may be lost when the power is cycled, and the instrument may not function
correctly. When Hewlett-Packard service replaces the battery, a revised boot
ROM may be installed.
Measurement cannot be performed on the selected waveform
The measurement is not defined for this waveform type, and cannot be made.
For example, the rise time of an A versus B waveform is not defined.
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