231-E140

Check Contactor Status in PLC Diagnostics

Navigate to PLC > Diagnosis > Inputs/Outputs and verify contactor feedback signals -AP1.x and -AP2.x show proper open/closed states during control startup.

Use the TNC's integrated oscilloscope function to monitor contactor switching timing

Measure Contactor Coil Resistance

Power down system and measure resistance across contactor coils. Typical values should be 180-220 ohms for 24VDC coils. Check for proper coil voltage at terminals.

Ensure LOTO procedures before accessing electrical components

Inspect Contact Points

Visually inspect main power contacts for welding, pitting, or carbon buildup. Replace contactors showing signs of contact welding or excessive wear.

Contactors with >500,000 switching cycles should be replaced preventively

Test Contactor Operation

Manually energize contactor coils and verify proper mechanical operation and contact resistance <1 milliohm across closed contacts.

Access Safety Circuit Diagnostics

Navigate to MOD > System Parameters > Machine Parameters and check MP7300.x series for safety circuit status. Verify all safety relay feedback signals are active.

Use MP7310 to enable extended safety diagnostics logging

Test Safety Relay Continuity

With power off, measure continuity through safety relay contacts in both energized and de-energized states. Verify proper isolation resistance >10 megohms when open.

Verify Safety Circuit Timing

Check MP7320.x parameters for safety circuit response times. Default values should be 50-100ms for proper pulse deletion test execution.

Never bypass safety circuits - replace faulty components only

Reset Safety Circuit

Perform safety circuit reset via PLC > Service > Safety Reset and monitor for proper initialization sequence completion.

Check Drive Status LEDs

Examine all status LEDs on motor drive modules. Red or flashing amber LEDs indicate internal faults. Record LED patterns for drive manufacturer diagnostics.

Monitor Drive Parameters

Access Machine Parameters MP1000-MP1999 series for axis-specific drive parameters. Check MP1010.x for drive fault history and MP1020.x for current monitoring values.

Use the TNC's trace function to log current values during startup sequence

Perform Drive Self-Test

Execute drive self-test via MOD > Diagnosis > Drive Test. This will isolate internal drive faults from external wiring issues.

Check Power Stage Isolation

With drive powered down, measure insulation resistance between motor phases and ground. Values should exceed 1 megohm per phase.

High voltage present - use appropriate PPE and test equipment rated for drive voltage levels

Perform Motor Insulation Test

Disconnect motor cables at drive and perform 500V megohm test between each phase and motor frame ground. Minimum acceptable value is 1 megohm.

Ensure motor is completely disconnected from drive before applying test voltage

Check Cable Continuity and Insulation

Test motor cable insulation and continuity. Look for damaged cable jackets, especially at cable carriers and entry points where flexing occurs.

Inspect Motor Terminal Box

Remove motor terminal box cover and inspect for moisture, contamination, or tracking marks on insulators that could create leakage paths.

Use thermal imaging to detect hot spots indicating poor connections or insulation breakdown

Verify Proper Motor Grounding

Ensure motor frame is properly grounded with <1 ohm resistance to machine ground. Check PE conductor continuity in motor cable.

Check TNC System Status

Navigate to MOD > Diagnosis > System Status and review all system fault logs. Look for recurring hardware fault patterns or memory errors.

Export diagnostic logs via Ethernet for detailed analysis

Verify Control Voltage Levels

Measure all control supply voltages at TNC terminals. 24VDC should be 24V ±10%, and any analog reference voltages should be within ±2% of nominal.

Use isolated measurement equipment to prevent ground loops

Perform TNC Self-Diagnostics

Execute comprehensive self-test via MOD > Service > System Test. This tests internal ADC circuits, memory integrity, and I/O functionality.

Update TNC Software

Check current software version against latest available. Update TNC software if known issues exist with pulse deletion test in current version.

Always backup machine parameters and PLC program before software updates