330-00B9

Access Drive Parameters

Navigate to MOD > Machine Parameters > Axes > Drive Parameters and check MP7380 (STO monitoring) settings for the affected axis.

Document current parameter values before making changes

Test STO Circuit Continuity

Use multimeter to verify STO.A.P.x signal path from TNC safety output to drive amplifier STO input terminals.

Ensure machine is in safe state and follow LOTO procedures before electrical testing

Verify Relay Operation

Manually trigger emergency stop and verify STO relay K1/K2 contacts open properly using oscilloscope on STO.A signal.

Check relay coil resistance - should be within 10% of nameplate value

Replace Faulty Components

Replace defective STO relay or safety contactor and verify proper wiring per machine electrical schematic.

Use only safety-rated components meeting PLd/SIL2 requirements

Check Drive Status Display

Access Service > Drive Status and verify STO channel status indicators match expected states during emergency stop activation.

Compare A and B channel status - they should mirror each other

Verify Drive Parameters

Check drive-specific STO configuration parameters via DRIVE-CLiQ interface or JH inverter parameter set P9601-P9610.

Incorrect STO parameters can create safety hazards

Measure STO Input Voltages

Verify 24VDC supply to STO inputs and measure voltage drop across STO.A terminals during normal and emergency conditions.

STO inputs typically require <2V for OFF state and >15V for ON state

Replace Drive Module

If STO circuit testing confirms internal drive fault, replace drive amplifier and restore parameters from backup.

Perform complete safety function test after drive replacement

Access Safety Diagnostics

Navigate to Service > Safety > Diagnostics and check STO channel status in real-time monitoring display.

Use F12 key to refresh diagnostic display continuously

Verify Safety Parameters

Check MP7350-MP7390 safety-related machine parameters for correct STO configuration and timeout values.

Safety parameters require special authorization level to modify

Test Safety I/O Module

Swap safety I/O modules if available, or use diagnostic software to test individual STO output channels.

Safety modules often have LED indicators showing channel status

Replace Safety Hardware

Replace faulty TNC safety board or I/O module and restore safety configuration from backup file.

Complete safety validation required after hardware replacement

Visual Wiring Inspection

Inspect all STO wiring from TNC X142/X143 safety connectors to drive STO terminals for damage or loose connections.

Pay special attention to cable flex points and connector strain reliefs

Continuity Testing

Perform end-to-end continuity test on STO.A.P.x signal path using multimeter with machine power off.

Disconnect drive power before performing continuity tests

Insulation Resistance Test

Test insulation resistance between STO conductors and ground using 500V megohmmeter - should exceed 10MΩ.

Test at multiple points along cable run to isolate fault location

Repair or Replace Wiring

Repair damaged conductors or replace entire STO cable harness using proper safety-rated cable.

Use only shielded, safety-rated cable meeting machine specifications