231-8B90

Check drive interface connections

Verify all connections on the digital drive interface (EnDat/1Vpp cables) between TNC and drive amplifier. Check X401/X402 connectors on drive unit.

Power down system before checking connections

Verify drive parameters in MP7500

Access Machine Parameters MP7500 series (Drive Interface) and verify correct drive type and interface settings match your amplifier model.

Compare with backup parameter file if available

Check drive amplifier status LEDs

Examine status indicators on drive amplifier. Green LED should be solid when ready. Flashing or red LEDs indicate internal drive faults.

Consult drive amplifier manual for LED diagnostic codes

Test with axis isolation

Set MP1010 (Emergency Stop) to isolate suspect axis and test if other axes initialize properly to isolate the faulty drive.

Document original MP1010 settings before modification

Check mechanical brake operation

Verify servo motor brake is engaging properly during E-STOP condition. Measure brake coil resistance and check 24V brake supply voltage.

Brake resistance should typically be 90-200 ohms depending on motor size

Inspect axis for external forces

Check for gravity loads, hydraulic pressure, or other external forces causing axis drift. Verify counterbalance systems are functioning.

Support heavy vertical axes before brake testing

Verify position feedback stability

Check encoder signals in TNC Diagnostics menu. Access MOD function and select 'Position values' to monitor for position drift during standstill.

Position should be stable within ±1 encoder count during standstill

Adjust MP1020 standstill monitoring

Review Machine Parameter MP1020 (Standstill monitoring window) settings to ensure appropriate tolerance for your application.

Do not increase MP1020 beyond mechanical requirements

Check DC bus voltage

Measure DC bus voltage at drive amplifier. Should be approximately 1.35 × AC input voltage. Verify voltage is stable and within ±10% tolerance.

Use appropriate PPE when measuring high voltage DC bus

Inspect power connections

Check all power connections to drive amplifier including AC input (L1,L2,L3), DC bus, and motor connections (U,V,W). Look for loose connections or heat damage.

Thermal imaging can reveal loose connections before visible damage occurs

Test drive amplifier isolation

Disconnect motor cables and attempt drive initialization. If successful, motor or motor cables may be faulty. If still failing, drive amplifier requires replacement.

Tag and photograph all connections before disconnecting

Review drive fault history

Check drive amplifier internal fault log if available. Many drives store fault history that can indicate root cause of power module failure.

Document all fault codes before clearing for service technician reference

Perform TNC diagnostic test

Access TNC Service menu and run built-in servo interface diagnostics. Check for communication errors or timeout conditions in test results.

Service menu access may require special key combination - consult TNC manual

Check TNC servo interface parameters

Verify Machine Parameters MP7400 series (Servo Interface Configuration) are correctly set for your drive system configuration.

Incorrect MP7400 settings can damage drive hardware

Test with parameter reset

Backup current parameters and restore TNC to factory defaults for servo interface settings. Test if alarm clears with default configuration.

Use TNC backup/restore function to save current settings before reset

Verify TNC software version compatibility

Check TNC software version against drive amplifier compatibility matrix. Older TNC software may not support newer drive models.

TNC software updates should only be performed by qualified technicians