231-C025

Access Service Display

Enter MOD 71 (Service Display) to access the error log. Note the timestamp and frequency of C025 errors to determine if the fault is intermittent or continuous. Check which CC component address is reporting the error.

If errors occur at regular intervals or during specific machine operations, this suggests vibration-related connector issues rather than a failed component.

Power Down and Inspect Connectors

Switch off main power and wait 5 minutes for capacitor discharge. Open the control cabinet and locate the CC6241 boards. Inspect X116 (first CC bus connection) and X216 (second CC bus connection) connectors for bent pins, discoloration, or debris.

Ensure main power is OFF and verify with voltage meter before touching any components. Residual voltage can remain in capacitors.

Reseat and Secure Connections

Disconnect and reconnect all CC-CC bus cables at both ends. Ensure the locking tabs engage fully. Check that cable strain relief is properly secured and cables are not under tension. Verify shielding connection at both connector ends.

Apply a small amount of contact cleaner (Kontakt 61 or equivalent) to the connector pins if any oxidation is visible. Allow to dry completely before reconnection.

Replace Suspect Cable

If physical damage is found or errors persist, replace the CC-CC bus cable with genuine Heidenhain part. Use cables with correct length and shielding specification (typically ID: 547300-xx depending on configuration). Route away from power cables with minimum 10cm separation.

Keep spare CC bus cables in inventory as they are critical components. Part numbers are configuration-specific, so reference the control's documentation or service parts list.

Verify Cable Routing

Inspect the routing of CC-CC bus cables inside the cabinet. Ensure they maintain minimum 10cm (4 inch) separation from AC power cables, servo drive power lines, and motor cables. Check that cables follow designated cable trays or routing channels.

Even DC power cables carrying high switching currents (like those to servo drives) can induce significant noise. Treat them as high-voltage for separation purposes.

Check Shield Grounding

Verify that the cable shield is properly terminated at both ends of the CC bus cables. The shield should have 360-degree contact with the connector backshell and low-impedance connection to the control cabinet ground. Use an ohmmeter to verify shield continuity and measure resistance to protective earth (should be <1 ohm).

Never leave cable shields floating at one or both ends on CC bus cables. This creates an antenna effect and worsens EMI susceptibility.

Test Under Load Conditions

Monitor alarm occurrence while running typical machining programs that activate servo drives and spindle. Access the PLC program status or use MOD function to observe real-time CC communication status during axis movement. Note if errors correlate with specific machine events.

If errors occur only during spindle operation or rapid traverse moves, this strongly indicates EMI coupling from those systems.

Install Ferrite Filters if Necessary

If EMI is confirmed, install snap-on ferrite cores on the CC bus cables near both connectors. Use cores with appropriate impedance for the frequency range (typically 50-200 MHz). Ensure cores do not prevent proper connector seating.

This should be a temporary diagnostic step. Properly routed and shielded cables should not require additional filtering. Persistent need for ferrites indicates a grounding or shielding problem elsewhere.