NEXSYS® Component Technology – Sensors & Detectors

ARINC 429 Multi-Bit Converter

The ARINC 429 Multi-Bit Converter (SR429/4M) from Applied Avionics can convert up to four different bits from a single ARINC 429 data label to discrete outputs. The polarity of the four outputs is selectable by bit. The SR429/4M is an 8-pin device, expandable to a 12-pin device.

The ARINC converter circuitry inside the SR429/4M includes an internal Health Monitor that can provide a “fail” indication if power to the decoder is lost or upon loss of valid ARINC data input. The Health Monitor has a range of watchdog timings requiring a valid ARINC label to be received within a specified time interval. The Health Monitor signal can be selected as one of the discrete outputs.

No software, firmware or programmable logic.
No stand-alone decoder required to achieve annunciation based on data bits.
Watchdog timer available to monitor validity of incoming ARINC data stream.

ARINC 429 Multi-Bit Converter Block Diagram

How it Works

The SR429/4M is an 8-pin device that converts up to four ARINC 429 data bits to discrete outputs. The polarity of each output (Open when Bit = 1 or Ground when Bit = 1) can be selected by bit. Bits can be repeated (taking two outputs) in order to get both polarities of the same bit. The internal Health Monitor can also be a selected output, with polarity option (Normal = Ground, Fail = Open or Normal = Open, Fail = Ground).

Additional Options

By increasing to a 12-pin package, the standard and inverted polarities of the four selected bits can be available.
Also in an expanded 12-pin package, the four discrete bits can be supplemented with a 2 X 4 decode of the two SSM bits (Bits 30 and 31) with polarity options. Additionally, the internal Health Monitor can be used in place of the SSM decode “00.”