231-A090

Check FSoE Connection Status

Press MOD key → System → Diagnostics → Safety. Review the FSoE Master/Slave status display. Look for red indicators showing communication errors or timeout conditions for the affected axis drive.

FSoE uses dual-channel monitoring with CRC validation. Even a single packet loss can trigger drive lock if the watchdog timer expires (typically 10-50ms window).

Verify EtherCAT Physical Layer

Navigate to MOD → System → Diagnostics → EtherCAT. Check topology display for cable errors, missing slaves, or increased error counters on the safety drive node. Inspect cable connections at both TNC EtherCAT interface and drive terminals.

Do not hot-plug EtherCAT cables while system is powered. Disconnect 24VDC supply before inspecting connections.

Review Safety Communication Parameters

Access MOD → Machine Parameters → FSoE Configuration. Verify FSoE_Connection_ID, FSoE_CRC, and watchdog timeout values match the drive's safety parameter settings exactly. Document any mismatches.

The FSoE CRC is calculated during safety validation. Any parameter change requires complete safety re-validation and new CRC generation.

Check Drive Safety Firmware Version

In MOD → System → Diagnostics → Drives, check the safety firmware version of the affected drive. Cross-reference with the TNC NC software version compatibility matrix in the FSoE implementation documentation.

Heidenhain TNC 640 with safety software version 3.x requires specific drive safety firmware versions. Mismatched versions cause intermittent FSoE protocol errors.

Perform Safety System Restart

After resolving communication issues: 1) Clear alarm with CE key, 2) Navigate to MOD → PLC → Safety Reset (if available), 3) Cycle the safety acknowledge input, 4) Monitor FSoE status return to green before enabling axes.

Safety restart procedures must follow machine-specific validated sequences. Consult machine safety validation documentation before proceeding.

Identify Active Safety Function

Press MOD → PLC → Inputs/Outputs. Locate safety input section (typically marked with yellow background in display). Check status of STO, SS1, SLS, and protective device inputs. Note which signal(s) show inactive or triggered state.

On TNC 640 with SafetyIntegrated, safety inputs are displayed with real-time dual-channel status. Both channels must agree or discrepancy error triggers drive lock.

Check Safety Door and Guard Interlocks

Physically inspect all machine guards, doors, and light curtains. Verify proper closure and that interlock switches are making contact. Cross-reference physical state with PLC input display showing guard positions.

Never bypass or defeat safety interlocks. All protective devices are part of validated safety system and must function correctly.

Review Emergency Stop Circuit

Check all E-stop buttons are released (rotated/pulled as applicable). Verify E-stop relay status in MOD → PLC → Inputs/Outputs shows both channels active. If E-stop circuit includes external safety relays, verify their status LEDs.

TNC controls monitor E-stop through both hardwired STO inputs and safety PLC logic. Both paths must be clear for drive enable.

Test SLS Configuration

If machine uses Safely-Limited Speed, access MOD → Machine Parameters → Safety Functions → SLS. Verify that current axis position and commanded speed are within configured safe limits. SLS violation locks drive until condition clears.

SLS zones are position-dependent. Check if axis is in a limited-speed zone where recent speed command exceeded the safe threshold for that area.