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DISCRETE to ARINC 429

The function of this converter is to encode up to 19 discrete inputs into a single ARINC 429 data word and transmit it.

The value of the ARINC 429 label, the SDI and the SSM are configurable by the user via miniature DIP switches located on the printed circuit board (PCB).  The transmission rate (bit rate and repetition rate) of the ARINC 429 word can also be configured via DIP switches.

All inputs and outputs for the converter are protected against lightening to RTCA DO-160G.

Sense inputs can be individually configured via DIP switches to be Open/Source (28V DC) or Open/Sink (0V) inputs.

The unit is powered from an external 28 VDC (18-72V) nominal supply, which is fused at an internal current limit of 500mA and thermal limit of 102 ºC. The power inputs are also reverse polarity protected.

No microprocessor - RTCA DO-178B not required.

DISCRETE to ARINC 429 Detail

ARINC429 Discrete description

Discrete data presented to the “sense inputs” are mapped directly to the transmitted ARINC 429 word bits 11 thru 26 respectively and can be either Source or Sink inputs on an individual basis depending upon the configuration of DIP switches (See later) on the PCB.

If discrete inputs are configured to be a “Sink” inputs then grounding the respective inputs will result in a logic ‘1’ bit in the respective bit within the transmitted ARINC 429 word.

If a discrete input  are configured to be a “Source” input then applying greater than 15.5 volts DC to the respective input will result in a logic ‘1’ bit in the respective bit within the transmitted ARINC 429 word.

A further 3 inputs designated “Open/Ground inputs” only are mapped to bits 27 thru 29 on the transmitted ARINC 429 word. These 3 inputs are Sink sense inputs only, but the corresponding transmitted bit for each input can be individually inverted by configuration of DIP switches on the PCB. Without inversion configured, grounding each of these“Open/Ground inputs” will result in Bits 27, 28 or 29 assuming a logic '1'' state in the transmitted ARINC 429 word.

ARINC429 transmitter description

The ARINC 429 Label field is user configurable via a DIP switch on the PCB. In addition the ARINC 429 SDI bits (bits 9 and 10) and SSM bits (bits 30 and 31) are also configurable via a DIP switch. The next 19 bits comprise a discrete data field as defined in ARINC Specification 429 Part 1, Attachment 6 “Discrete word format”. Bits 11 through 29 reflect the state of discrete sense input pins and their logic states are dependent upon the sense input configuration settings. The ARINC 429 transmitted parity bit is Odd by default.

The bit rate (12.5kHz/100kHz) of the transmitted ARINC 429 data word is set by a DIP switch on the PCB.

The converter will transmit ARINC 429 words at the maximum possible rate allowed by the ARINC 429 specification. That time is equal to 36 bit periods (32 data bits plus 4 gap times). For high speed ARINC 429, the word interval is 360 us, and for low-speed ARINC 429, the word interval is 2.88 mS.

The ARINC 429 word repetition rate may be set via another set of DIP switches on the PCB in intervals of 10mS from 10mS to 2.55 seconds. However, if the DIP switch is set to a timer value of zero the transmitted ARINC 429 word is transmitted at intervals of 360 uS when the speed is set to 100kHz and at 2.88mS when the speed is set to 12.5kHz.

See the downloadable user manual for full details.

DISCRETE to ARINC 429 Specifications

The YED/DIS19-A429-T1 has the following features: -

 

Physical

The YED/DIS19-A429T1 attaches to the airframe via four mounting holes. 

Height………………………………………       31.0mm

Width……………………………………….       90.0mm

Length…………………………….…..……     166.0mm

Weight………………………….…….…….     410 grams (approx.)

 

Electrical

Input Voltage………………………………     28V DC (15 to 72V DC operational)

Input Current……………………………....     50mA maximum at 28V DC

Reverse polarity protected.

Electrically fused …………………………     500mA(non-resettable)

Thermally fused …………………...……..     102 ºC.(non-resettable)

 
EMC       
             Internal lightning protection circuitry for both discrete sense lines and line driver allows                compliance with RTCA/DO-160G, Section 22 Level 3 Pin Injection Tests.

 

ARINC 429 Output

Label Value ………………………………      DIP Switch selectable

SSM ……………………………………….     DIP Switch selectable.

SDI ………………………………………...     DIP Switch selectable.

Parity ……………………………………...     ODD Parity – fixed.

Bit Rate …………………………………...     12.5kHz or 100kHz DIP Switch selectable

Label transmission rate ………………..      360uS to 2.55 Seconds. See later for details.

 

Sense Inputs

Format………………………….............….     Individual discrete Source (28V DC) 

                                                                    or Sink to Ground. Mapped to bits 

                                                                    11 thru 29.Bits 27, 28 & 29 opto-coupled

                                                                    sink inputsand sense polarity output 

                                                                    can be inverted.

 

Environmental

Operating temperature range…...…....…   -40 to +85 degrees C.

DISCRETE to ARINC 429 Downloads

   
download Click here to download the user manual in pdf format.
[Size: 1606kB]
[PASSWORD PROTECTED - To request password click here.]
 
   
   
 
   

Discrete to ARINC 429 Converter