HP 8920A, User Manual

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Chapter 3, Operating Overview
Saving and Recalling Instrument Setups
BASE Settings
The BASE register contains any field settings the user has saved that are different
from the instrument preset state. It establishes a reference point for all future
saves. If a base is not saved, the preset state is used as the reference.
When you save an instrument setup, the new setup is compared to the base
settings, and any differences are stored under the register name you supply.
Because only differences are stored, a much larger number of instrument setups
can be saved than if the contents of every field was saved.
When you recall an instrument setting, every field is reset to the base settings. The
saved settings are then used to re-establish the desired instrument setup.
CAUTION: Since each save/recall register only contains the differences between the setup being saved and
the present base register settings, changing the base settings causes all other saved setups to be
erased from memory (including the POWERON setting if one has been saved).
Unless you consistently change the same fields to the same value each time you use the
instrument, you should avoid creating your own BASE settings.
Memory Considerations
When the
Save/Recall
field of the I/O CONFIGURE screen is set to
Internal
, programs are saved to the same non-volatile RAM used to create
RAM Disk(s) and run IBASIC programs. By saving a large number of instrument
setups, you reduce the amount of RAM available to run programs. If you get a
“memory overflow” message while trying to load a program, you must clear one
or more save/recall registers to free RAM space.
Instrument Hardware Changes
Recalling a saved register that uses a hardware option that has been removed
(such as an audio filter) results in unspecified operation. Re-install the needed
option before attempting to recall the associated register(s).