A:
Even if communication is possible with a short CAN communication cable,
CAN communication may not be possible in the actual environment.
There are various possible reasons why CAN communication may not be possible,
but we recommend that you first check the termination resistor.
CAN communication requires 120Ω termination resistors at both ends of
the communication path.
If a frequency signal is transmitted without a termination resistor, the
reflected signal will mix with the original signal, and the signal may
not be read correctly.
CONTEC CAN devices are equipped with a function that allows you to select
whether or not to insert a termination resistor using the DIP switch on
the device.
For details, please refer to the manual for your device.
Example of the CAN communication bus that requires insertion of a terminating resistor :