User Manual

Appendix - "Bus analysis" mode
143
12.15.3. Measurements (RS232)
Diagnosis
Use this table to troubleshoot problems on a measurement :
Measurement
Description
Diagnosis
VLevel High
Measurement of the signal high level

Termination problem

Cable length not compliant with standard

Chassis-ground disturbance problem

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)

…
VLevel Low
Measurement of the signal low level
Time Data
Measurement made using the bit time
total

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)

Cable length not compliant with standard

Unsuitable or damaged cable

…
Time Rise
Rise time between -3V and 3V

Cable length not compliant with standard

Unsuitable or damaged cable (the rise and fall
times increase with the cable impedance)

…
Time Fall
Fall time between 3V and -3V
Jitter
Measurement made using the bit time
total

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)

…
Over+
Positive overshoot measurement

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-
Negative overshoot measurement