231-D300

Power down the control safely

Switch off the main power to the control and wait at least 5 minutes for capacitors to discharge before opening the cabinet.

Ensure proper lockout/tagout procedures. High voltage remains present after power-off.

Inspect HSCI cable connections

Locate the X116/X117 connectors on both the CC board and the SPL board indicated by the HSCI address in the alarm. Examine for bent pins, corrosion, or physical damage.

Use a flashlight to inspect the connector pins carefully. Even slight bending can cause intermittent CRC errors.

Reseat HSCI ribbon cables

Disconnect and reconnect the X116/X117 HSCI ribbon cables at both ends, ensuring they are fully seated with the locking tabs engaged. Check for cable strain or pinching.

Mark cable orientation before removal to ensure correct reinstallation. The ribbon cable has a specific pin 1 orientation.

Power up and verify

Restore power to the control and monitor for alarm recurrence. Check Service>System Info>Communication Status to verify HSCI link status.

Allow the control to run for at least 30 minutes under normal operation to confirm the issue is resolved.

Verify HSCI cable routing

Inspect the routing of X116/X117 HSCI cables inside the control cabinet. Ensure they are routed away from motor power cables, spindle inverter cables, and switching power supplies with minimum 100mm separation.

HSCI cables should never be bundled with power cables or run parallel to them for more than 50mm.

Check cabinet grounding

Verify proper PE (protective earth) connections at the control cabinet. Measure resistance between cabinet frame and earth ground - should be less than 0.1 ohms. Check for paint or corrosion at grounding points.

Use a calibrated low-resistance ohmmeter for accurate ground measurements.

Install EMI shielding if needed

If cable rerouting is not possible, install ferrite cores on the HSCI cables near both connector ends. Use Heidenhain-approved ferrite cores (part number available from service documentation).

Wrap the cable 2-3 times through the ferrite core for maximum EMI suppression.

Verify inverter cable shielding

Check that all motor and encoder cables have properly grounded shields at both the control and motor ends. Look for damaged cable shields or missing ground clamps.

360-degree shield grounding at cable glands is critical for EMI immunity on high-speed communication buses.

Identify the affected SPL module

Note the HSCI address from the alarm message (%1 value). Access Service Mode by holding MOD key during power-up, navigate to System Info > Hardware Configuration to identify which SPL board corresponds to that address.

Write down the SPL board position and serial number before proceeding with further diagnostics.

Check SPL board LED indicators

Power up the control and observe the LED indicators on the identified SPL board. A healthy SPL shows steady green power LED and blinking communication LED. Red LED or no activity indicates board failure.

Observe LEDs with cabinet powered - do not touch boards while power is applied.

Verify SPL firmware version

In Service Mode, navigate to System Info > Firmware Versions and verify the SPL board firmware matches the CC board requirements. Incompatible firmware causes communication protocol errors.

If firmware mismatch is found, update SPL firmware via MOD function before replacing hardware.

Perform SPL board swap test

If multiple SPL boards are present, power down and swap the suspect SPL board with a known-good SPL from another slot. Power up and check if the alarm follows the board or stays with the slot.

Ensure proper ESD precautions when handling circuit boards. Use grounded wrist strap.