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Heidenhain Controller
Power Supply · Intermediate · 30-120 minutes
HEIDENHAIN 231-C4C0 - C4C0 No motor current
Alarm 231-C4C0 indicates the TNC control cannot detect motor current feedback from the specified axis drive. This typically occurs when the motor connection is interrupted, the inverter module has failed, or there's a mismatch between the configured motor parameters and the actual motor installation.
231-C4C0
HEIDENHAIN 231-C4C0 - C4C0 No motor current
C4C0 No motor current
This TNC7/TNC 640 system error indicates Motor connected incorrectly or not at all (contactor). The control has detected an abnormal state that requires attention.
Root Cause Summary
Alarm 231-C4C0 indicates the TNC control cannot detect motor current feedback from the specified axis drive. This typically occurs when the motor connection is interrupted, the inverter module has failed, or there's a mismatch between the configured motor parameters and the actual motor installation.
Safety
- Refer to Heidenhain service manual
- Ensure qualified technician performs repairs
Causes and Fixes
- 1
Check Motor Contactor Status
Access MOD function and navigate to DIAGNOSIS > DRIVE STATUS to verify contactor engagement signals for the affected axis.
Listen for audible contactor click during axis enable sequence
- 2
Verify Motor Power Connections
Inspect U, V, W motor power cables at both motor terminal box and drive output terminals for loose connections or damage.
Ensure machine power is OFF and LOTO procedures followed before inspecting connections
- 3
Test Contactor Coil Resistance
Measure contactor coil resistance and verify 24VDC control voltage is present at contactor terminals during axis enable.
Typical contactor coil resistance should be 200-500 ohms depending on model
Call a technician if:
- ·Drive module replacement required
- ·Motor replacement needed
- ·DC link voltage issues persist
- ·Multiple axes affected simultaneously
Prevention
- Regular inspection of motor connections during PM
- Monitor drive temperatures and cooling system
- Keep motor parameter backups updated
- Implement vibration monitoring for early bearing failure detection
Common Mistakes
- Assuming motor failure without checking connections first
- Clearing alarm without identifying root cause
- Incorrect motor parameter entry during replacement
- Not verifying DC link voltage before drive replacement
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Always verify with your machine manual or a certified technician before performing service procedures.