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Heidenhain Controller
Safety · Intermediate · 30-120 minutes
HEIDENHAIN 239-0192 - 192 MC-FSUC: voltage monitoring impaired
Alarm 239-0192 indicates the FS (Functional Safety) microcontroller has detected a fault in its internal voltage monitoring circuits. This typically occurs when the safety controller cannot reliably monitor its own power supply voltages, compromising the integrity of safety functions.
HEIDENHAIN 239-0192 - 192 MC-FSUC: voltage monitoring impaired
192 MC-FSUC: voltage monitoring impaired
This safety-related error indicates a fault in the FS microcontroller. The FS microcontroller reports defective monitoring of the voltage. The control has detected a safety issue that may affect safe operation.
Root Cause Summary
Alarm 239-0192 indicates the FS (Functional Safety) microcontroller has detected a fault in its internal voltage monitoring circuits. This typically occurs when the safety controller cannot reliably monitor its own power supply voltages, compromising the integrity of safety functions.
Safety
Causes and Fixes
Check FS Power Supply Voltages
Access MOD function, navigate to DIAGNOSIS > HARDWARE INFO > POWER SUPPLY and verify all FS-related voltage rails are within specification (typically ±5% tolerance).
Use a quality DMM to verify actual voltages at the FS controller terminals match the displayed values.
Inspect Power Supply Connections
Power down system and check all connections to the FS power supply module, looking for loose terminals, corrosion, or heat damage on X101 connector.
Always follow LOTO procedures and wait for capacitor discharge before touching power connections.
Test Power Supply Under Load
Monitor voltage stability during machine operation cycles, particularly during high-current servo moves that may cause voltage drops.
Voltage drops exceeding 2-3% during operation often indicate aging power supply components.
Replace FS Power Supply Module
If voltage instability is confirmed, replace the dedicated FS power supply module and reconfigure safety parameters through MOD > SAFETY CONFIG menu.
FS power supply replacement requires safety system recertification and parameter backup/restore.
Call a technician if:
Prevention
Common Mistakes
Seeing Multiple Alarms?
Seeing another alarm with this one? Enter the code.
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