Metrix OX9302-BUS, User Manual

Page: 116 / 143

Appendix - "Bus analysis" mode
116
12.3.3. Measurements (CAN High-Speed)
Diagnosis
Use this table to troubleshoot problems on a measurement :
Measurement Description Diagnosis
Vdiff Dom
Measurement of the Vdiff dominant
state

Termination problem (load too light)

Junction connection (oxidation, bad contact,
etc.)

Cable length not compliant with standard

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)

…
Vdiff Rec
Measurement of the Vdiff recessive
state
VCanH Dom
Measurement of the Vcan dominant
state

Chassis-ground disturbance problem

Common mode problem

Cable length not compliant with standard

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)

Junction connection (oxidation, bad contact,
etc.)

…
VCanH Rec
Measurement of the Vcan recessive
state
Time Rise
Rise time between 10% and 90% of
the VDiff signal amplitude

Unsuitable or damaged cable (the rise and fall
times increase with the cable impedance)

Termination impedance positioned incorrectly

…
Time Fall
Fall time between 90% and 10% of the
VDiff signal amplitude
Time Data
Measurement made using the bit time
total

Unsuitable or damaged cable

Termination impedance positioned incorrectly

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)

…
Jitter
Measurement made using the bit time
total

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)

…
Over +
Measurement of the positive overshoot
compared to the Vdiff signal amplitude

Unsuitable cable impedance

Bus termination problem (termination absent,
major overshoot)

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)

…
Over -
Measurement of the negative
overshoot compared to the Vdiff signal
amplitude