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KUKA Robot Controller
Communication · Basic
KUKA Robot KRC0664 - InterBus: bus error in slave ring
A communication error has occurred in the InterBus ring network connecting the KRC4 controller to higher-level systems such as a PLC or safety controller. This bus error in the slave ring indicates a complete or intermittent loss of communication in the chain that coordinates multi-device automation sequences. The error prevents reliable data exchange between the master controller and slave devices.
KRC0664
KUKA Robot KRC0664 - InterBus: bus error in slave ring
InterBus: bus error in slave ring
A communication error has occurred in the InterBus ring network connecting the KRC4 controller to higher-level systems such as a PLC or safety controller. This bus error in the slave ring indicates a complete or intermittent loss of communication in the chain that coordinates multi-device automation sequences. The error prevents reliable data exchange between the master controller and slave devices.
Common Causes
- Physical disconnection or power loss in one of the InterBus slave devices in the ring topology
- Defective InterBus cable or connector causing open circuit in the communication ring
- Slave device firmware or configuration mismatch with the KRC4 master controller expectations
- Excessive electromagnetic interference from external sources disrupting InterBus signal integrity
- Slave ring termination resistor failure or incorrect termination configuration at ring endpoints
Troubleshooting Steps
- 1Verify that all InterBus slave devices in the ring are powered on and responding with status indicators
- 2Inspect the entire InterBus ring cabling from the KRC4 controller through all slave devices for breaks or loose connectors
- 3Check the InterBus ring termination configuration using WorkVisual to confirm proper 120-ohm resistors are in place at both ring ends
- 4Power cycle all InterBus slave devices sequentially after confirming the KRC4 controller is operational
- 5Review the slave device configuration in WorkVisual to ensure firmware versions match the KRC4 controller build version
- 6Replace the InterBus cable or suspected slave device if no communication is restored after the above steps, and perform a full ring communication test
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