NetAlert NetMeter User Manual page 18

CANH/L Diff. V (R)
CANH/L differential (Recessive) shows you the
difference between CANH and CANL for recessive bits:
CANH/L diff. V(R) = CANHV(R) - CANLV(R)
5MEJ?D
Display
MIN
MAX
Why is this measurement important?
Data bits (0's and 1's) are transmitted as differences in
voltage between the CANH and CANL wires. The
differential voltage measurements are essentially a
measurement of "signal quality".
The recessive differential voltage is ideally zero, but
typically is +/- a few millivolts.
A recessive differential voltage that is not sufficiently
close to zero may be mis-interpreted by a transceiver as
a dominant bit - resulting in communication errors.
7
250
V
250
x 1
V
250
x 2
V
Recessive differential bus
voltage can not be
measured because the
bus is stuck dominant.
9 11
What it means
Current CANH/L
recessive voltage
differential is 0.09V.
Minimum CANH/L
recessive voltage
differential since the
NetMeter was
plugged in or reset is
0.08V.
Maximum CANH/L
recessive voltage
differential since
NetMeter was
plugged in or reset is
0.09V.
7
18