Serial bus analysis
R&S
®
RTM3000
332User Manual 1335.9090.02 ─ 09
Word Format
Figure 13-46: Structure of an ARINC 429 word
An ARINC 429 word is 32-bits and consists of the following parts (see Figure 13-46):
●
Parity: the most significant bit (MSB). Checks if there are bit errors during the trans-
mission. The total number of logic 1 bits for the word shall be odd.
●
Sign/Status Matrix (SSM): the value of these bits depends on the data type. It may
be used to report the status of hardware equipment.
●
Data:
– Binary (BNR): stores the data as a binary number.
– Binary Coded Decimal (BCD): uses 4 data field bits to represent a decimal
digit.
– Discrete data: a combination of BNR and/ or BCD or individual bits that express
specific equipment conditions.
– Maintenance data and acknowledgment
– Williamsburg / Buckhorn protocol: a bit-oriented protocol that is used for file
transfer.
●
Source/Destination Identifier (SDI): indicates the intended receiver or the transmit-
ting subsystem.
●
Label: gives information about the word's data type.
For comfortable analysis, you can load an editable label list, to interpret transferred
numeric values as meaningful text labels.
13.9.2 ARINC 429 configuration
The correct setup of the protocol parameters and the threshold is the condition for
decoding the signal.
To set up and decode a ARINC 429 signal
1. Press the [Protocol] key in the Analysis area of the front panel.
2. Select the bus that you want to use: B1, B2, B3 or B4.
3. Select the "Bus Type" = ARINC 429.
4. Select "Configuration".
5. Select the "Source", the channel to which the input signal is connected.
6. Set the threshold:
ARINC 429 (option R&S
RTM-K7)
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