www.vtiinstruments.com
APPENDIX D
109
S
ELF
C
ALIBRATION
L
OG
The calibration log simply consists of a series of informational messages about the progress of
calibration, each accompanied by a timestamp. The following are some of the types of message
that can appear:
•
connect to localhost:9900: Setting up the socket to read data from the instrument
•
setup: Setting up the measurement settings needed during calibration
•
warmup: Waiting a few seconds to ensure that any previously disabled ADCs are warmed up and
settled
•
measure X freq Y range Z: Measuring voltage reference X using clock frequency Y and range Z
•
restore user configuration: Restoring all settings to the values they had before calibration was
started
•
save results: Creating new results file and storing in volatile memory
•
check limits: Comparing calculated calibration adjustments to minimum and maximum valid
values
•
apply adjustments: Overwriting currently loaded self calibration adjustments with the newly
calculated ones
•
failed: an error has occurred
o
Unable to synchronize: was not able to synchronize ADCs.
o
Current full calibration does not match this card: The currently loaded full calibration does
not match this card’s programmed model and serial numbers.
o
Current full calibration date is in the future: The currently loaded full calibration can’t be
valid because it hasn’t happened yet.
o
Current date/time is invalid: The current time is invalid because it’s before the release of this
firmware.
o
CHX Y Hz, range Z: A of B exceeds limits of C - D: When calculating adjustment A on CHX
at a clock frequency of Y Hz and range Z, the value was B, which falls either below the
minimum value of C or above the maximum of D.
o
failed I/O: Unable to retrieve measurement data from the ADCs.
o
crashed: the self calibration code has a bug.
•
success: Completed all steps successfully.
C
ALIBRATION
R
ESULTS
The calibration results file contains all the same information as the Calibration Adjustments. It
also
includes more information about the measurements that went into calculating each adjustment
value.
That additional information takes the following form:
•
Measurements:
o
Channels:
▪
CH1 - CHN: a list of measurement objects, each containing:
•
Reference: The name of the voltage reference being measured
•
Range: The range being used to do the measurement
•
Clock Frequency: The clock frequency used to do the measurement
•
Min: A list of the minimum value from each of the records acquired during the
measurement
•
Max: A list of the maximum value from each of the records acquired during the
measurement
