230-04B4

Check SMC Status Display

Navigate to MOD function → System Info → SMC Status to verify SMC module communication state and response times.

Look for response times exceeding 50ms as indication of communication issues

Verify Ethernet Connection

Check physical Ethernet cable connections between TNC and SMC module, ensure secure connections at both X116 (TNC) and SMC Ethernet ports.

Power down system before checking connections to prevent damage

Test Network Configuration

Access Setup → General → Network Settings and verify SMC IP address configuration matches machine parameter MP7755 (SMC_IP_ADDRESS).

Use ping test from TNC diagnostic menu to verify SMC network reachability

Reset SMC Communication

Execute SMC reset via MOD function → Reset → SMC Reset, then monitor for alarm recurrence during next safety cycle.

SMC reset will temporarily disable safety functions - ensure machine is in safe state

Monitor CPU Utilization

Check MOD function → System Info → Performance Monitor to identify CPU usage patterns and peak load conditions exceeding 85%.

Document CPU usage during specific machining operations to identify load patterns

Review Active NC Programs

Analyze current part program for excessive computational blocks like complex spline interpolations or high-frequency position updates that burden the processor.

Look for G06.1 NURBS blocks or sub-micron resolution moves that increase processing overhead

Optimize Cycle Time Parameters

Adjust machine parameter MP1020 (CYCLE_TIME_IPO) and MP1021 (CYCLE_TIME_PLC) to balance performance with system stability.

Increasing cycle times may affect machining precision - test thoroughly after changes

Disable Non-Essential Functions

Temporarily disable resource-intensive features like advanced surface inspection or real-time tool monitoring via Setup → Machine → Optional Functions.

Re-enable functions individually to isolate the specific cause of high CPU load

Verify SMC Software Version

Check MOD function → System Info → Software Versions and confirm SMC firmware version compatibility with current TNC software release.

Refer to Heidenhain compatibility matrix for approved SMC/TNC version combinations

Synchronize Safety Cycles

Access Setup → Safety → SMC Configuration and verify parameter MP7750 (SMC_SYNC_MODE) is set to 1 for synchronized operation.

Incorrect sync mode can cause unpredictable safety behavior

Reset Safety System

Perform complete safety system reset via Setup → Safety → Reset Safety System, then reconfigure all safety functions.

This will clear all safety configurations - have backup of safety parameters ready

Validate Safety Function Timing

Use SMC diagnostic mode to verify safety function execution times are within specified limits defined in MP7751-MP7759 timing parameters.

Safety functions should complete within 80% of allocated time window for reliable operation

Inspect SMC Module LEDs

Examine SMC module status LEDs - green should be solid, red should be off. Flashing patterns indicate specific hardware faults per SMC manual.

Document LED patterns and timing for accurate fault diagnosis

Test Interface Card Connections

Verify secure seating of SMC interface card in TNC rack slot, check for corrosion or damage on connector pins.

Power down completely before removing or reseating interface cards

Measure Signal Integrity

Use oscilloscope to verify acknowledgment signal levels at SMC interface connector meet specifications (24V ±10% for digital signals).

Check signal rise/fall times should be <1ms for proper SMC recognition

Replace SMC Module

If hardware tests fail, replace SMC module with known good unit and transfer safety configuration from backup.

SMC replacement requires complete safety system validation and approval before production use