bUS
Option Communication Error
Yaskawa · Drive Fault Codes
What does bUS mean?
An error occurred during communication with an installed option card (e.g., network card, encoder card). This indicates a problem with the data exchange between the main drive unit and the option module, which can disrupt control or feedback functions.
Common Causes
- Loose or improper physical connection of the option card to the drive's expansion slot
- Incorrect communication settings configured in drive parameters (e.g., network address, baud rate)
- Faulty option card hardware or an issue with the drive's internal communication interface.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Power down the drive completely and reseat the option card firmly into its slot.
- 2
Verify all communication parameters (e.g., network address, baud rate, data format) are correctly configured for the specific option card.
- 3
Check the cabling between the option card and any external communication network or device for integrity and proper connection.
Verified technical data. Last updated: March 2026
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Source: Yaskawa Drive Fault Codes