Metrix OX9302-BUS, Руководство пользователя

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Appendix - "Bus analysis" mode
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12.8.3. Measurements (FlexRay)
UBus = U_BP – U_BM
Diagnosis
Use this table to troubleshoot problems on a measurement :
Measurement Description Diagnosis
UBus High
Measurement of the high level on the
Ubus signal

Termination problem

Junction connection (oxidation, bad
contact, …)

Cable length not compliant with standard

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)

…
UBus Low
Measurement of the low level on the
UBus signal
Time Data
Measurement made using the bit time
total.

Unsuitable or damaged cable

Termination impedance incorrectly positioned

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)

…
TRise
Rise time between 20% and 80% of
the UBus signal amplitude

Unsuitable or damaged cable (the rise and fall
times increase with the cable impedance)

Termination impedance incorrectly positioned

…
TFall
Fall time between 80% and 20% of
the UBus signal amplitude
UCm
Offset measurement on the U_BP
signal

Chassis-ground disturbance problem

Common mode problem

Cable length not compliant with standard

…