Teledyne LeCroy CANbus TD and CANbus TDM - Operators Manual - Manual (Page 25)

Operator's Manual
CANbus-TD-TDM-OM-E RevB
25
Select the measurement level as Percent or Absolute, and set a value. Then select the slope of
the edge to which you want to measure. The Hysteresis selection imposes a limit above and
below the measurement Level, which precludes measurements of noise or other perturbations
within this band. The width of the band is specified in milli-divisions. Guidelines for using
Hysteresis are as follows:

Hysteresis must be larger than the maximum noise spike you want to ignore.

The largest value of hysteresis usable is less than the distance from the level to the
closest extreme value of the waveform.

Unless you know the largest noise and closest extreme level that will ever occur on any
cycle, leave some margin on both sides of the level.
Note: Various pathological conditions can block the computation of the CANtoAnalog and
CANtoCAN parameters. In all cases, the cause of the condition can be viewed on the message
line by clicking on the yellow icon , below the measurement parameter values.
The simplest, and most common, reason for non-computation of the CAN timing parameters is
that none of the CAN Message or Analog Signal conditions defined in the right-hand dialog is
encountered in the whole record processed by the algorithm. In this case the error message
will be "Cannot find Start and/or End condition on input of CAN2CAN or CAN2Analog."
Another possible cause is that the time frames of the 2 inputs specified do not overlap at all.
The error message will be "No Common Time Span exists between inputs"
Finally, the sequence of occurrence of the CAN Message or Analog Signal conditions defined in
the right-hand dialog setup tab can lead to ambiguous results. (Too many CAN conditions for
each Analog condition, nested CAN and Analog conditions). In this case the message line will
show: "Ambiguous Start/End time relationship for CAN2CAN or CAn2Analog".
CAN Message-to-CAN Message Measurement Parameter
CAN Message-to-CAN Message timing (CANtoCAN)
This measurement parameter is used to measure timing values between two CAN Messages.
The Frame Type, ID, DATA, etc. conditions for the CAN message can be fully defined for both
CAN messages. The timing is always measured from the End of Frame of the first CAN message
to the Start of Frame (SOF) of the second CAN message.