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Heidenhain Controller
Communication · Intermediate · 30-120 minutes
Heidenhain 245-0401 - Failed to send internal message
HEIDENHAIN alarm 245-0401 indicates a failure in internal system communication between TNC control modules, typically involving the NC kernel, PLC, or hardware interface components. This alarm occurs when message queues become corrupted, communication timeouts exceed system limits, or hardware communication paths fail.
245-0401
Heidenhain 245-0401 - Failed to send internal message
Failed to send internal message
Heidenhain TNC error 245-0401: Failed to send internal message. This alarm indicates a fault or error condition on the Heidenhain TNC control that requires investigation. Refer to the Heidenhain NC error message documentation for the specific cause and remedy for this alarm code.
Root Cause Summary
HEIDENHAIN alarm 245-0401 indicates a failure in internal system communication between TNC control modules, typically involving the NC kernel, PLC, or hardware interface components. This alarm occurs when message queues become corrupted, communication timeouts exceed system limits, or hardware communication paths fail.
Safety
- Refer to Heidenhain service manual
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Check System Load Status
Access MOD function, select 'System Info' and check CPU load and memory usage. Look for values exceeding 85% consistently.
Use Ctrl+T to access real-time system diagnostics while alarm is active
- 2
Clear NC Memory Buffers
Perform controlled shutdown via MOD > System > Shutdown, wait 30 seconds, then restart. This clears internal message queues.
Ensure all axes are in safe position before shutdown
- 3
Verify Program Complexity
Check if alarm occurs with specific programs. Reduce lookahead buffer in machine parameter MP7440 from default 100 to 50.
Complex spline interpolations can overload message buffers
- 4
Monitor Communication Timing
In Service menu, check 'Communication Statistics' for message timeout counters and reset if necessary.
Call a technician if:
- ·Hardware interface card replacement needed
- ·Multiple communication modules failing
- ·Persistent alarm after all software troubleshooting
Prevention
- Regular backup of machine parameters and PLC programs
- Monitor system load during complex machining operations
- Maintain proper control cabinet environmental conditions
- Keep NC software and firmware updated
Common Mistakes
- Ignoring high CPU load warnings that precede communication failures
- Modifying system communication parameters without proper documentation
- Not checking hardware connections before assuming software issues
- Performing emergency stops during active communication diagnostics
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Always verify with your machine manual or a certified technician before performing service procedures.