Master WARNING/CAUTION

This application diagram depicts a Master Warning & Caution flight deck annunciator that has built-in custom blink circuitry. Whenever the internal senses that the warning and caution signals are active, the respective indicator will blink at the chosen rate. 

The design uses a single annunciator that has a VIVISUN Compact Body which houses two NEXSYS Square Wave Oscillator (CT2) components. Both CT2s are configured to have high-z (open) outputs when inactive. The upper CT2 is configured to output a 1 Hz square wave when active, and the lower CT2 is configured to output a 2 Hz square wave when active. 

In the default state, the indicator is dead face and both signals are inactive. When the Master Caution signal becomes active, a low (ground) is present on input IN (A3) of the upper CT2. This causes a 1 Hz square wave to be produced from output OUT (A1) and the CAUTION (A) indicator to flash. This state is held so long as the Master Caution signal is active. When the Master Warning signal becomes active, a low (ground) is present on input IN (B3) of the lower CT2. This causes a 2 Hz square wave to be produced from output OUT (B1) and the WARNING (B) indicator to flash. This state is held so long as the Master Warning signal is active.

Disclaimer: The configurations and diagrams shown above are provided by Applied Avionics, Inc. as a general example only. The recipient is solely responsible for actual design, electrical wiring, validation, testing, applicability and functionality of the product in regards to the customer’s specific application.