APM
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

  1. 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.

How to clear it

  1. 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.

Confidence: high · Dedicated troubleshooting walkthrough naming machine series (ST60/ST80) and the specific failing component.

First sourced: 5/21/2026

Related alarms

Same control or a nearby code on the same machine.