5.4 - Data Buses Flashcards
What speed is the ARINC 629 data is?
2 megabits per second. Twenty times faster than ARINC 429
How many terminals can the ARINC 629 handle?
120 terminals sharing a bi directional serial data bus
What does Simplex mean in data exchange?
The transmission can flow only in one direction
What does Half Duplex mean in data exchange?
One transmitter, one receiver. The transmission can flow in both directions but only one direction at a time. (Bi-directional with limitations)
What does Full Duplex mean in data exchange?
One transmitter, one receiver. The transmission can flow in both directions at the same time (bi-directional)
What does a ARINC data bus look like?
A pair of twisted wires transmitting sets of information at periodic intervals
How does ARINC 429 check for accurate data reception
ARINC 429 prescribes the use of odd parity indication for error detection
How many transmitters and receivers are used on ARINC 429?
1 transmitter and up to 20 receivers
Can a receiver respond to a transmitter on ARINC 429
Yes, but never on the same data bus where the transmission occurred
What is the address of a LRU on the ARINC 429 network?
LRUs do not have addresses. They have equipment numbers which are grouped into equipment or system types
Advantages of serial transmission
- Only a single line is required for transmission
- Only one set of digital circuitry is needed to process the data
What are the transmission speeds of ARINC 429?
- Low Speed (LS BUS) 12-14 kbit/s
- High Speed (HS BUS) 100 kbit/s
How long are ARINC 429 words
32 bit words made of 1’s and 0’s. Separated by 4 bit times of null (zero volts)
What is BCD (Binary Coded Decimal) data used for?
Displays only, transmitted on average twice a second
What is BNR (Binary) data used for?
It’s processed by other LRUs and transmitted 6-20 times a second
What is the data word format for ARINC 429 in BNR?
1-8, 8 bit label
9-10, Source/Destination Identifier (SDI)
11-28, BNR data area
29-31, Sign/Status Matrix (SSM)
32, parity check
What is the data word format for ARINC 429 in BCD?
1-8, 8 bit label
9-10, Source/Destination Identifier (SDI)
11-29, BCD data area
30-31, Sign/Status Matrix (SSM)
32, parity check
How is the Label (Bit 1-8) transmitted
The MSB is in the LSB of the word and transmitted first on to the bus.