BACnet Unknown Object
The device returns Unknown Object when a Read or Write request references an object type or instance that does not exist. Common with mismatched point lists or configuration drift.
Common Causes
- BACnet point list in front-end does not match device’s actual object list
- Device firmware upgrade or reset changed object instances
- Typo in object type or instance (e.g., AV vs BV, wrong instance)
- Object was deleted or renamed in device configuration
Fix Steps
- Query the device Object List to get current objects and instances.
- Compare with front-end database; update point addresses to match.
- Verify object type (AI, AO, AV, BI, BO, BV, etc.) and instance number.
- If device was reconfigured, export updated object list and reimport to front-end.
- Document any deprecated points and remove or remap them.