Advanced Instruments, Inc.
Span Calibration
The transmitter is generally delivered calibrated and ready to use. However, in order to obtain reliable
data, the transmitter must be calibrated at the initial start-up and periodically thereafter. The maximum
calibration interval recommended is approximately 1-3 months, or as determined by the user’s
application.
Calibration involves adjusting the transmitter electronics gain (sensitivity) to the sensor’s signal output at
a given oxygen standard, e.g. a certified span gas with an oxygen content (balance nitrogen)
approximating 80% of the range of analysis or one range above the intended measuring range is
recommended for optimum accuracy, see Calibration and Accuracy. Calibration with ambient or
instrument air (20.9%) is recommended when installing a new sensor or when a certified gas is not
available.
Factory Default Span
The embedded software will remove previous span calibration data and reset the SPAN adjustment to the
factory default value based on the average oxygen sensor’s signal output. For example, after factory
default span, when a span gas is introduced, the micro-processor will display oxygen reading within
+50% of the span gas value when the sensor signal output is within its specification. If the sensor’s
signal output is outside of its specification, the oxygen reading will be /-50% of the span gas
value. This feature allows the user to test the sensor’s signal output without removing it from the sensor
housing.
Access the MAIN MENU by pressing the MENU key.
Advance the reverse shade cursor using the ARROW keys to highlight MANUAL SAMPLE.
Press the ENTER key to select the highlighted menu option. The following display appears:
Manual Span
The user must ascertain that the oxygen reading (actually the sensor’s signal output) has reached a
stable value within the acceptable limits before completing the span adjustment. Failure to do so will
result in an error.
MAIN MENU
AUTO SAMPLE
MANUAL SAMPLE
CALIBRATE
77 F
100 KPa
CALIBRATION
SPAN CALIBRATE
ZERO CALIBRATE
DEFAULT SPAN
DEFAULT ZERO
77 F
100 KPa
MAIN MENU
AUTO SAMPLE
MANUAL SAMPLE
CALIBRATE
77 F
100 KPa
CALIBRATION
SPAN CALIBRATE
ZERO CALIBRATE
DEFAULT SPAN
DEFAULT ZERO
77 F
100 KPa
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