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Heidenhain Controller
Safety · Intermediate · 30-120 minutes
HEIDENHAIN 330-00BC - CC error in cut-out channel STO.A.x (-STO.A.MC.WD=0) ax-grp. S
HEIDENHAIN alarm 330-00BC indicates a fault in the CC-specific Safe Torque Off (STO) cutout channel for spindle axis group S, where power module acknowledgment signals show incorrect readiness states. The alarm fires when at least one power module reports RDY.x=1 when all modules should report RDY.x=0 during STO activation.
330-00BC
HEIDENHAIN 330-00BC - CC error in cut-out channel STO.A.x (-STO.A.MC.WD=0) ax-grp. S
CC error in cut-out channel STO.A.x (-STO.A.MC.WD=0) ax-grp. S
An error occurred during initialization or cyclic operation of the internal I/O hardware. This affects communication with SPI modules.
Root Cause Summary
HEIDENHAIN alarm 330-00BC indicates a fault in the CC-specific Safe Torque Off (STO) cutout channel for spindle axis group S, where power module acknowledgment signals show incorrect readiness states. The alarm fires when at least one power module reports RDY.x=1 when all modules should report RDY.x=0 during STO activation.
Safety
- Refer to Heidenhain service manual
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Check STO Terminal Connections
Inspect terminals X521/X522 on the CC controller for loose connections and verify STO.A.x signal continuity using multimeter.
Disconnect power before checking STO circuit connections
- 2
Verify Power Module STO Inputs
Check STO input terminals on each spindle power module for proper 24V signal levels and secure connections.
Use TNC diagnostic screen MOD → DRIVE to monitor real-time STO signal states
- 3
Test STO Circuit Continuity
Perform continuity test from CC controller STO outputs through safety relays to power module STO inputs, checking for breaks or shorts.
Document wire colors and terminal positions before disconnecting for easier reassembly
Call a technician if:
- ·STO safety circuit modifications required
- ·CC controller hardware replacement needed
- ·Safety system validation required
Prevention
- Regular STO circuit testing during maintenance
- Monitor power module RDY signals during routine checks
- Keep safety relay contacts clean and properly torqued
Common Mistakes
- Bypassing STO circuits for troubleshooting
- Ignoring intermittent RDY signal fluctuations
- Mixing different power module firmware versions
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