VTI Instruments EX1000A, Руководство пользователя

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EX10xxA Web Page Operation 85
When linked as a limit event, a DIO channel will be cleared at the beginning of a new acquisition.
Its state will then be updated with each scan according to the programmed limit evaluations. By
default, the cleared state is low, but can be set on a per channel basis to be high through the selection
of the
Invert checkbox. Similarly, the default operation for each channel is non-latch mode, but can
be set on a per channel basis to be latch mode through the selection of the Latch checkbox. In latch
mode, a transition out of the cleared state would remain, regardless of future limit evaluations, until
it is cleared at the beginning of a new acquisition.
D
EVICE
M
ENU
The Device menu is used to perform advanced configuration operations on the EX10xxA/E.
Self-calibration
This action page is used to perform operations related to self-calibration. As discussed in
Self-calibration in Section 3, the measurement performance of the EX10xxA is significantly
improved through the periodic use of self-calibration. The self-calibration process completes
quickly and does not require removal of the actual input connections or the use of external
equipment, making it convenient to run often. In order to take full advantage of the self-calibration
system, it is important to understand how the self-calibration constants are generated, used, and
stored.
Self-calibration does not overwrite, modify, or take the place of the instrument’s nonvolatile
calibration constants generated by a full calibration. Instead, it generates an additional set of
calibration constants that are applied to the measurement calculation after the full calibration
constants. When self-calibration is performed, it places its calculated data in volatile memory. This
data is termed the “current self cal data” and is used automatically by the instrument. No additional
command is necessary. Because it is in volatile memory, however, it will be cleared upon an
instrument reset or power cycle. There is the ability, however, to store the current self cal data into
nonvolatile memory.
In order to perform a self-calibration, a lock on the instrument must first be acquired. For more
information on locking, refer to the
Locking Menu description in this section. If self-calibration is
attempted without the acquisition of a lock, an error message will be displayed. Within this page,
the self-calibration process is initiated by clicking on the
Perform Self Calibration button. Once
started, the page will confirm the initiation of the calibration process and then continuously refresh
with a percentage completion status until completed. Once the completion status reaches 100%, the
self-calibration process is complete.
To protect the user from performing a self-calibration while the instrument is warming up, a warning
message will be issued and calibration will not be performed if self-calibration is attempted before
the EX10xxA has been powered on continuously for 60 minutes. This is only a warning, however,
and it can be overridden with the
Override Self Calibration Uptime button that appears when this
warning is triggered. In general, this option should not be used, as performing self-calibration prior
to complete instrument warm-up could result in degraded measurement performance. However, it
would be appropriate to utilize the override in the case where the unit has actually been warmed up,
but has simply been subjected to a quick power cycle or reboot.
As noted above, the self-calibration operation places its calculated data in volatile memory, termed
“current self cal data.” Once present, it can be cleared by utilizing the
Clear Current Self Cal Data
button. This operation clears the volatile data, but does not affect any self cal data that is stored in
nonvolatile memory.