All alarm codes
ALARM 221
Turret Clamp Sensor Malfunction
Tool indexing failure on ST60/ST80 — turret clamp sensor (proximity switch on the turret face) is not signaling clamped position within the watchdog time.
- Controls
- Mazatrol 640T
- Machine series
- Mazak ST60, Mazak ST80
Causes
Tool indexing failure on ST60/ST80 — turret clamp sensor (proximity switch on the turret face) is not signaling clamped position within the watchdog time.
- Fabian Achavalyoutube
This video describes how to diagnose/troubleshoot tool indexing failures on Mazak ST60 and/or ST80.
- Fabian Achavalyoutube
How to clear it
- 1
Inspect and clean the turret clamp sensor (proximity switch on the turret face); verify the gap to the target tooth and that the wiring is intact.
- Fabian Achavalyoutube
M640T CNC: Alarm 221 Turret Clamp Sensor Malfunction Troubleshooting
- Fabian Achavalyoutube
Confidence: high · Dedicated troubleshooting walkthrough naming machine series (ST60/ST80) and the specific failing component.
First sourced: 5/21/2026