330-00BB

Check STO Circuit Connections

Inspect X521/X522 STO connector pins on each axis drive module for loose connections, corrosion, or damage. Verify 24V STO supply voltage at terminals.

Power down system and follow LOTO procedures before inspecting electrical connections.

Verify STO Signal Continuity

Use multimeter to test continuity of STO.A.MC.WD and STO.A.x signals from TNC control cabinet to each power module in axis group A.

Check for voltage drop across STO circuit - should be less than 2V under load.

Test STO Relay Operation

Manually activate/deactivate STO relays while monitoring RDY.x signals in TNC diagnostic screen MOD → Service → Drive Diagnosis.

STO relays should switch within 10ms - slower response indicates relay degradation.

Monitor Individual RDY Signals

Access TNC menu MOD → Service → Drive Diagnosis → Axis Group A and observe RDY.1, RDY.2, RDY.3 status for each power module during STO activation.

All RDY signals should simultaneously change to 0 within 50ms of STO activation.

Check Power Module Status LEDs

Visually inspect status LEDs on each power module - green LED should extinguish when STO is active, red fault LED may indicate internal module fault.

Do not touch power module heat sinks - temperatures can exceed 70°C during operation.

Perform Power Module Reset

Execute controlled shutdown, power cycle individual power modules, then restart system and test STO function through TNC menu PLC → Manual → Safety Functions.

Wait minimum 30 seconds after power down before restart to allow capacitor discharge.

Check DRIVE-CLiQ Cable Integrity

Inspect DRIVE-CLiQ cables between TNC and axis group A drives for damage, proper seating, and correct routing away from power cables.

DRIVE-CLiQ cables should maintain minimum 10cm separation from motor power cables.

Verify DRIVE-CLiQ Topology

Access TNC menu MOD → Service → Drive Diagnosis → DRIVE-CLiQ and confirm all axis group A drives show 'Connected' status with correct node addresses.

Never disconnect DRIVE-CLiQ cables while system is powered - this can damage communication modules.

Test DRIVE-CLiQ Signal Quality

Run DRIVE-CLiQ diagnostic test through TNC menu MOD → Service → Tests → Communication Test and check for transmission errors or timeouts.

Error rates above 10^-6 indicate cable or connector degradation requiring replacement.

Verify STO Monitoring Parameters

Check TNC machine parameter MP7300 (STO monitoring time) and MP7301 (STO response time) values match drive specifications - typically 50ms monitoring, 10ms response.

STO monitoring time should be 5x longer than maximum drive response time for reliable operation.

Review Axis Group Configuration

Verify machine parameters MP1010-MP1019 correctly define axis group A membership and that all axes in group have consistent STO configuration.

Changing axis group parameters requires complete system restart and safety function revalidation.

Validate Safety Function Settings

Access TNC menu MOD → Machine Parameters → Safety and confirm STO enable bits, monitoring channels, and cutout logic match machine documentation.

Use parameter backup/compare function to verify current settings against known good configuration.