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Heidenhain Controller
Communication · Intermediate · 30-120 minutes
HEIDENHAIN 303-000B - Invalid parent node
HEIDENHAIN alarm 303-000B occurs when an OPC UA object configuration references a PLC variable entity as its parent node, which violates the TNC's OPC UA hierarchy structure. This typically happens during OPC UA server configuration or when importing invalid configuration files that create improper parent-child relationships in the communication tree.
303-000B
HEIDENHAIN 303-000B - Invalid parent node
Invalid parent node
A PLC configuration or communication error has been detected. This affects the interaction between the control and the PLC system.
Root Cause Summary
HEIDENHAIN alarm 303-000B occurs when an OPC UA object configuration references a PLC variable entity as its parent node, which violates the TNC's OPC UA hierarchy structure. This typically happens during OPC UA server configuration or when importing invalid configuration files that create improper parent-child relationships in the communication tree.
Safety
- Refer to Heidenhain service manual
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Access OPC UA Configuration
Navigate to MOD function → Communication → OPC UA Server → Configuration to examine the current OPC UA node structure.
Document the current configuration before making changes for rollback purposes.
- 2
Identify Invalid Parent References
Review the OPC UA object tree and locate any CfgOpcUaObject entries that reference CfgOpcUaPlcVar entities as parent nodes.
Do not modify configuration while machine programs are running.
- 3
Restructure Node Hierarchy
Modify the parent reference to point to a valid CfgOpcUaObject or root node instead of the PLC variable entity.
Use the TNC's built-in configuration validator to check hierarchy before applying changes.
- 4
Restart OPC UA Service
Cycle the OPC UA server service through MOD → Communication → OPC UA Server → Service Control to apply the corrected configuration.
Call a technician if:
- ·Configuration file corruption persists after multiple restore attempts
- ·PLC integration requires custom programming
- ·Software version update needed
Prevention
- Always validate OPC UA configurations before importing
- Maintain proper node hierarchy documentation
- Regular backup of working OPC UA configurations
- Test configuration changes in non-production environment first
Common Mistakes
- Setting PLC variables as parent nodes for OPC UA objects
- Importing configurations from incompatible TNC versions
- Not validating configuration files before deployment
- Modifying OPC UA settings during active machine operation
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