User Manual

Appendix - "Bus analysis" mode
115
12.1.3. Measurements (ARINC 429)
Diagnosis
Use this table to troubleshoot problems on a measurement:
Measurement
Description
Diagnosis
High AB
Measurement of the signal high
level

Termination problem

Cable length not compliant with standard

Faulty junction connection (oxidation, bad
contact, etc.)

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)
 …
Low AB
Measurement of the signal low
level
Null AB
Measurement of the signal in
idle level

Unsuitable or damaged cable (load too light)

Cable length not compliant with standard

Faulty junction connection (oxidation, bad
contact, etc.)

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)
Time Rise
Rise time

Cable length not compliant with standard

Unsuitable or damaged cable (the rise and fall
times increase with the cable impedance)
 …
Time Fall
Fall time
Bit Time
Bit duration

Cable length not compliant with standard

Unsuitable or damaged cable

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)
 …
½ Bit Time
Half a bit duration