Front Panel Description - PRESTON PRESSURE ALT-621 Operation And Maintenance Manual

Front Panel Description

The UNITS button is used to toggle between the various units of measurement.
The UNITS button on the ALT-621 will toggle between a display of feet, meters, mbars,
and inHg.
The UNITS button on the ASP-621 will toggle between a display of MPH, KPH, or
Knots.
The EXIT button is used to exit out of the leak check mode.
The LEAK CHECK will begin a 120 second timer, and the display will also show the
gain or loss of altitude or airspeed experienced during the displayed time period. If the
operator wishes to select a different length of time, the Leak Check button may be
pressed repeatedly, which will cause a reduction in the timer counter in 30-second
increments. The timer will not toggle above 120 seconds nor under 30 seconds. Once the
time is selected, press the Units button to start the timer.
The LIGHT button will toggle the display backlight ON or OFF.
Note: there is no method provided to turn the power on or off. If this function is
necessary, an external switch will have to be added.
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