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Heidenhain Controller
Communication · Intermediate · 30-120 minutes
HEIDENHAIN 220-0018 - General internal communication error
This alarm stems from a failure in the internal data exchange between the TNC's central processing unit and critical subsystems like the PLC controller or axis processors. Most commonly, this is caused by hardware connection issues with internal modules, firmware incompatibilities after updates, or actual component failure on the MC or CC boards. Power instability and low buffer battery voltage can also corrupt communication protocols.
220-0018
HEIDENHAIN 220-0018 - General internal communication error
General internal communication error
This TNC7/TNC 640 error (220-0018) relates to 'General internal communication error'. An error has occurred in the system-inherent communica- tion.
Root Cause Summary
This alarm stems from a failure in the internal data exchange between the TNC's central processing unit and critical subsystems like the PLC controller or axis processors. Most commonly, this is caused by hardware connection issues with internal modules, firmware incompatibilities after updates, or actual component failure on the MC or CC boards. Power instability and low buffer battery voltage can also corrupt communication protocols.
Safety
- Refer to Heidenhain service manual
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Power Down and Access Control Cabinet
Safely power down the machine and TNC control. Lock out electrical supply and wait 2 minutes for capacitor discharge before opening the control cabinet.
High voltage remains in control components after shutdown. Follow all lockout/tagout procedures.
- 2
Reseat CC Module
Locate the CC module on the backplane (typically labeled CC or PLC). Carefully remove the module by releasing locking clips, inspect connectors for corrosion or damage, then firmly reseat ensuring full engagement with audible click.
Mark connector orientation before removal. Clean connector contacts with isopropyl alcohol if any discoloration is visible.
- 3
Inspect Backplane Connector
Examine the backplane connector pins for bent contacts, burn marks, or debris. Use compressed air to clean the connector area and ensure no foreign material is present.
Never use contact cleaners with oil or residue on control components.
- 4
Power Up and Test
Restore power and monitor startup sequence. If alarm clears, run a complete PLC cycle test and axis reference run to verify stable communication.
If alarm clears temporarily but returns, the CC module itself is likely failing and requires replacement.
Call a technician if:
- ·Hardware component failure confirmed
- ·System file corruption cannot be resolved
- ·Multiple communication subsystems failing simultaneously
Prevention
- Maintain proper cabinet ventilation and temperature control
- Perform regular system file backups
- Monitor PLC cycle times and system performance regularly
- Keep TNC software updated to latest stable version
Common Mistakes
- Ignoring intermittent communication warnings before failure
- Not backing up system configuration before troubleshooting
- Attempting to modify communication parameters without understanding system architecture
- Overlooking environmental factors affecting hardware reliability
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Always verify with your machine manual or a certified technician before performing service procedures.