This article addresses communication issues on the CAN bus when using Ixxat CAN-IB PCIe boards and USB-to-CAN interfaces. It guides users through essential checks such as wiring, termination, baud rate settings, and signal quality to identify and resolve common CAN bus problems.
APPLICABLE PRODUCTS
CAN-IB100/PCIe, CAN-IB200/PCIe, CAN-IB300/PCI, CAN-IB400/PCI, CAN-IB520/PCIe mini, CAN-IB600/PCIe, USB-to-CAN V2, USB-to-CAN FD, CAN@net NT
QUESTION
Why is my CAN bus not working properly?
ANSWER
Please check the following things:
- Are all CAN nodes connected correctly with each other?
a) Are the CAN cable and CAN connectors alright?
b) Is a standard CAN cable used?
c) Are CAN_H, CAN_L and CAN_GND of the CAN nodes connected with each other?
d) Is the CAN cable shielded?
e) Is the Shield grounded at one side?
- Is the CAN bus terminated with two CAN termination resistors?
- Is the maximum CAN bus length not exceeded?
- Are at least two CAN nodes connected to the CAN bus?
Please note:
a) For CAN communication at least two CAN nodes are required, because of the CAN acknowledgement.
b) CAN nodes in „Listen Only“ mode do not send the acknowledgement.
- Is the same CAN baud rate set for all CAN nodes?
- Is the same CAN mode set for all CAN nodes?
(standard (11bit ID) or extended (29bit ID)?)
- Do all CAN nodes work according to the same CAN standard?
(ISO 11898 [ISO99-2] (CAN-High-Speed) or ISO 11519 [ISO99-3] CAN-Low-Speed (Fault-Tolerant)).
- Are there electrical disturbances on the CAN bus?
- Are there CAN Error Frames on the CAN bus?
- If you are not able to solve problem, please send to us a CAN topology scheme with the following data
a) Wire length
b) CAN baudrate
c) Location of both CAN termination resistors
d) Number and type of connected CAN nodes
- You can check the quality of the CAN signal using a CANcheck, PCAN-Diag or an oscilloscope?
- Please send us screenshots of the CAN signal oscilloscope.