Racal Instruments 1256 Manual page 130

Publication No. 980855 Rev. A
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The SYSTEM:NVUPD and SYSTEM:NVUPD? query are used to
both initiate and determine whether a non-volatile update cycle is
in progress.
To improve system reliability and eliminate the need for batteries,
the 1256 stores configuration information into flash memory. The
downside of flash memory is that it updates more slowly than
battery-backed memories.
To minimize the effects of the flash memory update cycle, the 1256
allows individual selections (i.e. include list, exclude lists, path
names, menu selections, etc) to be instantaneously saved into
intermediate volatile memory. When all of these intermediate
operations are completed, the SYSTEM:NVUPD command starts
the actual process of transferring the contents of intermediate
volatile memory into non-volatile flash memory with a single,
slower update.
For example, the command:
SYST:NVUPD
will cause the 1256 to start the transfer process.
The command:
SYST:NVUPD?
will return:
ACTIVE
during the update process and:
IDLE
at any other time or after the update process has completed.
Attempting to change intermediate memory during a flash update
cycle is prohibited. To illustrate this point, sending a MOD:SAV
while SYST:NVUPD? returns ACTIVE, will cause the 1256 to
ignore the request and push an error onto the system error queue.
These commands are NOT defined in the SCPI standard. These
commands follow the syntax rules of SCPI to implement this
functionality.
1256 User Manual
SCPI Command Basics 5-41