Description (AMM 22-01-10/34-28-01)

 

Two digital/analog adapters, identified as 1 and 2, are mounted on the E1-2 shelf in the electrical and electronics equipment bay. The units convert digital data inputs to analog, and analog data to digital. The units provide the interface data requirements for the IRS and FMCS. The DAA automatically receives IRU and DADC fault data from the IRU after landing, then stores it together with DAA fault data. When interrogated during IRS BITE, the DAA transmits IRU, DADC, and DAA fault data to the FMC.

 

The digital to analog adapter (DAA) is a component of the inertial reference system (IRS) but is interfaced with other airplane systems for processing signals independent of the status of the IRS. The two DAAs accept inputs in various formats, primarily ARINC 429, and convert them to outputs compatible with various airplane systems and instruments.

 

The DAAs accept ARINC 429 inputs from the IRUs and convert the 429 format into analog signals with associated valids to control the presentations on various displays.

 

The DAA's are installed on the E1-2 rack in the electrical and electronic

compartment.