Separate Host Detection from CAN Communication
The computer detects the PCAN interface, but the connected equipment no longer communicates. Treat these as separate checks: host detection confirms that the computer can recognize the interface; it does not confirm correct CAN cabling, termination, bit-rate configuration, or transceiver operation.
| Observation | What it confirms | What remains unverified |
|---|---|---|
| PCAN is detected by the computer | The host recognizes the interface | CAN wiring and transceiver operation |
| BUSHEAVY or bus-off appears | The fault occurs while attempting CAN communication | Matching bit rates and correct termination |
Check Bit Rate and Termination
Prioritize the two configuration and wiring conditions identified in the evidence:
- Configure the PCAN interface and every connected CAN device for the same bit rate.
- Verify that the CAN cable has a 120-ohm termination resistor between CAN-L and CAN-H at each end.
- Reconnect and test communication. If the error remains, perform the documented PCAN transceiver check with a voltmeter; use the applicable hardware procedure because no voltage limits are provided here.
Verify the Reported Rate Threshold
The fault was reported when the PCAN-View bit-rate setting was above 100 bit/s, but the evidence does not establish whether that unit and threshold were recorded correctly. Capture the exact PCAN-View setting and units, then compare them directly with the configured bit rate of every other node. Do not select a replacement value by trial alone; the required value is the one shared by all devices on the network.
After correcting the bit rate or termination, verify that PCAN-View communicates without BUSHEAVY or bus-off. If both conditions are correct and the error persists, the voltmeter-based transceiver check separates a possible interface hardware fault from the network configuration checks already completed.
FAQ
Why is PCAN detected but not communicating with the equipment?
Computer detection verifies host recognition only. Check that every CAN node uses the same bit rate and that both cable ends have 120-ohm termination between CAN-L and CAN-H.
What causes PCAN-View BUSHEAVY or bus-off errors?
For this reported fault, investigate mismatched CAN bit rates and missing or incorrect end termination first. If those checks pass, test the PCAN transceiver with the documented voltmeter procedure.
Where should the 120-ohm CAN termination resistors be connected?
Install one 120-ohm resistor between CAN-L and CAN-H at each end of the CAN cable.