BACnet Write Access Denied
The device rejects a WriteProperty request because the object or property is read-only, locked by a higher priority, or explicitly configured to deny writes. Common with physical inputs or protected setpoints.
Common Causes
- Writing to read-only object (e.g., analog input instead of analog value)
- Higher-priority value in array blocking the requested priority
- Object property out-of-service or write disabled in device config
- Missing or insufficient priority for command (e.g., default instead of manual)
Fix Steps
- Confirm you are writing to a writable object (AV, BV, AO, BO, etc.), not AI/BI.
- Read priority array; relinquish or null higher-priority values if needed.
- Use appropriate priority (8 = operator, 1 = manual-life-safety, etc.) per application.
- Check device config: enable writes, remove out-of-service, or adjust security.
- Verify COV subscriptions or other clients are not holding conflicting values.