Mazak Nexus Series Error Codes
Mazak Nexus series (QTN, QT, VCN, VCS, HCN) machines use the Mazatrol MATRIX CNC or SMOOTHG control. Alarms display on the CNC screen with a number and description. Alarms are grouped by category: 1xx (servo), 2xx (spindle), 3xx (PC/control), 4xx (OT/limit), 5xx (ATC/APC), 6xx (chuck/tailstock).
Nexus Alarm Code Table
| Code | Fault Description | Common Cause | Action |
|---|---|---|---|
| 50 | Emergency stop | E-stop activated | Release and check cause |
| 100 | Servo alarm ΓÇö X axis | Servo drive or motor fault | Check servo drive |
| 200 | Spindle alarm | Spindle drive fault | Check spindle drive |
| 201 | Spindle overspeed | Speed above maximum | Check program S code |
| 300 | Control unit alarm | NC/PC communication fault | Check PC board |
| 400 | Overtravel ΓÇö positive | Axis past positive limit | Move axis, check limits |
| 401 | Overtravel ΓÇö negative | Axis past negative limit | Move axis, check limits |
| 500 | ATC alarm | Tool changer fault | Check ATC sequence |
| 501 | Magazine alarm | Magazine positioning fault | Check magazine servo |
| 600 | Chuck fault | Chuck not clamped | Check hydraulic pressure |
| 601 | Tailstock fault | Tailstock positioning fault | Check tailstock control |
| 700 | MPC alarm | Machine parameter error | Check machine parameters |
| 800 | ATC carrier alarm | Carrier positioning fault | Check carrier servo |
Most Common Nexus Faults
100/200 ΓÇö Servo/Spindle Alarms
Nexus servo alarms refer to the Mazak servo pack (FANUC-based). Check servo amplifier LED on cabinet door. Alarm LED codes: 1 = overload, 2 = regeneration, 3 = DC bus, 4 = IGBT, 5 = feedback, 6 = communication. Match LED reading to specific remediation.
400/401 ΓÇö Overtravel
Work offset or tool offset entered incorrectly. In MDI mode with E-stop released, hold SHIFT + override axis in JOG mode to move axis back into travel range. Then review all offsets before resuming production.
500 ΓÇö ATC Alarm
Mazak Nexus ATC sequence is programmable. Check which step in the M6 sequence fails ΓÇö view ATC sequence diagram in the machine maintenance screen. Common causes: proximity switch failure, servo positioning error, or mechanical jam.
600 ΓÇö Chuck Fault
Check hydraulic pressure (minimum 900 PSI for standard chucks). Verify workpiece is seated correctly. If chuck relay is suspected, check PLC input in the Mazatrol diagnostic screen.
Parts Commonly Needed
| Part | Notes |
|---|---|
| Servo pack | Amazon | Match axis and current rating |
| Encoder battery | Amazon | Absolute encoder backup |
| ATC proximity switches | Amazon | Check position in sequence diagram |
| Hydraulic pressure switch | Amazon | Chuck and tailstock circuits |
| Coolant pump | Amazon | Check impeller and motor amps |
Pro tip: Mazak Nexus stores alarm history with timestamps in the ALARM LOG menu. Access via MAINTENANCE → ALARM LOG. Historical data shows if an alarm is intermittent (temperature-related) or consistent (mechanical or electrical failure).