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Operating Instructions - CPA2501
Air Data Test Indicator
CPA2501
Auxiliary buttons can be placed in three different parts of the screen depending on how they are set in the
Transducer Application. Each auxiliary display can be modified by pressing the displayed button.
Peak: Pressing the Peak button will reset the upper and lower peak value to the current reading, subse-
quent negative or positive divergence from that reading will be recorded in the button.
Rate: Pressing the Rate button will display a choice of time rate units for the rate denominator.
Units: Pressing the Auxiliary Units button will display the same set of units available for the primary units.
Pressing any of these units will change the auxiliary units to that chosen unit.
6.4.1.3 Zero Button
If the Zero Calibration function has been chosen in the Transducer App (section 6.4.4), then the Zero Cal
Button [
] will appear in the Measure App. If the channel is measuring absolute pressure, and the
Zero Cal Button is pressed, a keyboard will appear to allow entry of a known pressure (from an appropri-
ate standard) for a single point calibration. If the channel is in Qc Mode, measuring gauge pressure, or
in gauge emulation mode, pressing the button will calculate an offset and set the current reading to zero.
For all of these gauge modes, the offset value will not be saved to the transducer but will only be active
temporarily. After exiting the emulation mode or after a power cycle, the temporary offset adjustment will
be cleared. The zero adjustment for an absolute channel, not in emulation mode, will be saved to the
transducer as if single point calibration had been performed.
Figure 6.4.1.3 shows Ps and Qc channels in Ps/Qc pressure mode, the zero cal function has been en-
abled for both channels and there is a barometric reference installed. The screen on the left shows both
channels with zero buttons. The screen on the right shows the same two channels, but the zero button
on the absolute channel has been pressed, showing the keypad enabled to accept a new single point
calibration value.
Figure 6.4.1.3 - Zero Button, Gauge - Absolute
The background color of the zero button will momentarily change to a lighter color as the zero calibration
is performed then will revert back to a darker color when complete.
