231-6003

Check Machine Enable Relay Status

Navigate to MOD function → Machine Parameters → MP7300.x series to verify enable relay status and check physical relay K1 in electrical cabinet.

Ensure main power is locked out before checking relay contacts

Verify Enable Chain Continuity

Use multimeter to check continuity through complete enable chain from TNC to servo drives, including all safety relays in series.

Check MP7310.0 (Machine ON input) parameter assignment matches actual hardware wiring

Test Relay Coil Voltage

Measure 24VDC supply to enable relay coil and verify proper switching voltage levels at relay contacts.

Intermittent voltage drops often cause this alarm during high current draw operations

Check Emergency Stop Status

Verify all E-STOP buttons are properly reset and check MP7320.x parameters for emergency stop input assignments.

Do not bypass safety circuits - identify and correct the safety violation

Inspect Safety Door Switches

Test all safety door switches and guards, verify proper operation and check MP7330.x safety door input parameters.

Vibration can cause intermittent door switch contact issues

Validate Safety Chain Logic

Use TNC diagnostic screen (MOD → Diagnosis → PLC Status) to monitor safety input states in real-time during operation.

Record which safety input changes state when alarm occurs

Measure 24VDC Supply Voltage

Check 24VDC supply voltage at TNC terminals and verify it remains above 20.4VDC minimum during operation.

Use oscilloscope to capture voltage drops during spindle start or rapid axis movements

Check Power Supply Loading

Calculate total current draw on 24VDC supply and verify power supply capacity is not exceeded.

Overloaded power supplies can cause intermittent voltage drops

Inspect Power Supply Connections

Check all 24VDC supply connections for corrosion, loose terminals, or voltage drops across connections.

Measure voltage drop across each connection point - should be less than 0.1V

Test Input Module Function

Navigate to MOD → Diagnosis → Digital Inputs to monitor machine-on input state and verify it matches actual signal voltage.

Compare adjacent input readings to identify module-specific failures

Swap Input Assignments

Temporarily reassign machine-on input to different input terminal via MP7310.0 parameter to isolate hardware failure.

Document original parameter values before making changes

Check Input Module LED Status

Verify input module LED indicators match expected states and check for any fault indicators on TNC input cards.

Flickering LEDs often indicate marginal input threshold conditions