231-A082

Check SPLC Status in MOD Function

Access MOD > System Info > SPLC Status and verify the status of SPLC output module %2. Look for hardware fault indicators or channel mismatch reports.

Document the exact SPLC output number and variable number from the alarm for targeted diagnostics.

Verify Output Module Connections

Inspect the physical connections to SPLC output module %2, checking for loose terminals, damaged cables, or corroded contacts on both A and B channel connections.

Ensure machine is in safe state and follow LOTO procedures before inspecting electrical connections.

Test Output Module Functionality

Use TNC diagnostic functions to manually activate the affected SPLC output and monitor both channels using an oscilloscope or multimeter to verify signal integrity.

Compare signal timing and voltage levels between A and B channels - they should be identical within tolerance.

Replace SPLC Output Module

If hardware fault is confirmed, replace the SPLC output module following Heidenhain safety system procedures and perform complete safety validation.

Safety system modifications require certified technician and complete safety validation per EN ISO 13849.

Review Safety Configuration

Access MOD > Machine Parameters > Safety Parameters and verify configuration of SPLC output %2, checking cross-comparison settings and tolerance values.

Compare current settings with machine documentation or backup parameter files.

Check Parameter MP7300 Series

Verify machine parameters MP7300-MP7399 (Safety PLC parameters) for correct SPLC output configuration, particularly cross-comparison enable settings.

Never modify safety parameters without proper authorization and safety validation.

Validate Cross-Comparison Settings

Check MP7350.x parameters for cross-comparison configuration of the affected SPLC output, ensuring proper A/B channel correlation settings.

Use parameter comparison function to identify recent changes to safety parameters.

Restore Known Good Configuration

If parameter corruption is suspected, restore safety parameters from validated backup and perform complete safety system verification.

Safety parameter restoration requires complete machine safety validation and may require safety system recertification.

Monitor SKERN Communication Status

Access MOD > System Info > SKERN Status and check communication statistics between Safety Kernel and SPLC system for errors or timeouts.

Look for cyclic communication errors or increased response times in the SKERN diagnostics.

Check Safety Bus Integrity

Verify safety communication bus connections and termination resistors, ensuring proper signal integrity for dual-channel safety communication.

Safety bus modifications require system shutdown and proper ESD precautions.

Restart Safety System

Perform controlled restart of SKERN safety system through MOD > System > Safety System Restart to clear communication buffers and re-establish proper cross-comparison.

Monitor alarm occurrence pattern after restart - intermittent alarms suggest communication issues.

Update SKERN Firmware

Check for available SKERN firmware updates that address cross-comparison communication issues and apply if recommended by Heidenhain.

Safety system firmware updates require complete safety validation and may affect safety certification.

Identify Connected Safety Device

Determine which safety device (safety relay, contactor, valve, etc.) is connected to SPLC output %2 using machine electrical schematics and I/O documentation.

Check machine documentation for SPLC I/O assignment table to quickly identify the affected safety function.

Test Safety Device Operation

Manually test the identified safety device operation, checking for proper dual-channel response and feedback signal generation on both A and B channels.

Ensure machine is in safe state before testing safety devices - some tests may require bypassing safety functions.

Measure Feedback Signals

Use multimeter or oscilloscope to measure actual feedback signals from the safety device to verify both channels are providing identical responses.

Look for timing differences between channels - even microsecond delays can trigger cross-comparison alarms.

Replace Faulty Safety Device

If safety device shows channel mismatch or delayed response, replace with identical safety-rated component and verify proper dual-channel operation.

Safety device replacement must maintain same safety integrity level (SIL) and requires functional safety validation.