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Heidenhain Controller
Safety · Intermediate · 30-120 minutes
HEIDENHAIN 231-E1C0 - E1C0 RDY.x status of spindle stays active (safety relay)
Alarm 231-E1C0 indicates the spindle safety relay (STOS) system is not properly disabling the spindle drive when commanded. The '-STOS.A.G' signal remains at high level instead of switching to active low level, preventing proper safety lockout of the spindle power stage.
231-E1C0
HEIDENHAIN 231-E1C0 - E1C0 RDY.x status of spindle stays active (safety relay)
E1C0 RDY.x status of spindle stays active (safety relay)
During the safety-relay test, the -STOS.A.G spindle signals stayed at the inactive level although the MC commanded the active state. The spindle power stage is therefore not being locked by the safety signal.
Root Cause Summary
Alarm 231-E1C0 indicates the spindle safety relay (STOS) system is not properly disabling the spindle drive when commanded. The '-STOS.A.G' signal remains at high level instead of switching to active low level, preventing proper safety lockout of the spindle power stage.
Safety
- Refer to Heidenhain service manual
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Check Safety Relay Status
Navigate to MOD function → Machine Parameters → MP7300.x series to verify STOS configuration and status bits.
Use PLC program to monitor real-time STOS signal states
- 2
Measure STOS Output Voltage
With multimeter, measure voltage at '-STOS.A.G' terminal on safety relay module. Should read 0V when active, 24V when inactive.
Ensure machine is in safe state before accessing electrical terminals
- 3
Test Relay Coil Continuity
Power down system and test safety relay coil resistance. Replace relay module if coil shows open circuit or incorrect resistance values.
Follow LOTO procedures before electrical testing
Call a technician if:
- ·Safety system modifications required
- ·Drive replacement needed
- ·Parameter backup/restore required
Prevention
- Regular STOS system testing during PM
- Keep parameter backups current
- Monitor safety relay contact wear
Common Mistakes
- Bypassing safety circuits temporarily
- Incorrect MP7300 parameter modification
- Ignoring intermittent STOS faults
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Always verify with your machine manual or a certified technician before performing service procedures.