Lenze 940 Servo Drive Fault Codes:
| Fault Code and Meaning | Cause and Remedy |
|---|---|
| F_OU Over voltage | Cause: Drive bus voltage reached the maximum level, typically due to motor regeneration. Remedy: Check deceleration time or install a braking resistor. |
| F_FB Feedback error | Cause: Invalid Hall sensors code; Resolver signal lost or at least one motor hall sensor is inoperable or not connected. Remedy: Check encoder/resolver wiring and Hall sensor connections. |
| F_OC Over current | Cause: Drive exceeded peak current limit. Software incapable of regulating current within 15% for more than 20mS. Remedy: Check for wrong motor data, poor tuning, or short circuit in motor cables. |
| F_Ot Over temperature | Cause: Drive heatsink temperature has reached maximum rating (100°C or 108°C depending on model). Remedy: Check ambient temperature, cooling fans, and cabinet ventilation. |
| F_OS Over speed | Cause: Motor has reached velocity above its specified limit. Remedy: Check speed loop tuning and commanded velocity limits. |
| F_PE Position Error Excess | Cause: Position error has exceeded maximum allowed value. Remedy: Check for mechanical jams, motor sizing, or increase position error tolerance. |
| F_bd Bad motor data | Cause: Motor profile data is invalid or no motor is selected. Remedy: Verify motor parameters in the configuration software. |
| F_EP EPM failure | Cause: EPM (Electronic Programming Module) failure on power up. Remedy: Replace the EPM module or try re-seating it. |
| -EP- EPM missing | Cause: EPM not recognized (connected) on power up. Remedy: Ensure the EPM is properly inserted into the slot. |
| F_09 Motor over temperature | Cause: Motor over temperature switch activated or PTC indicates motor windings reached maximum temperature. Remedy: Allow motor to cool; check motor load and cooling. |
| F_10 Subprocessor failure | Cause: Error in data exchange between processors. Usually occurs when EMI level is high. Remedy: Check for poor shielding and grounding of the system. |
| F_14 Under voltage | Cause: Bus voltage level drops below 50% of nominal bus voltage while operating. Remedy: Check incoming AC line voltage and power supply stability. |
| F_15 Hardware overload protection | Cause: Phase current becomes higher than 400% of total drive current capability for more than 5μs. Remedy: Check for short circuits or extreme mechanical overload. |
| F_18 Arithmetic Error / Division by zero | Cause: Statement executed within Indexer Program results in division by zero. Remedy: Check and correct the drive source code logic. |
| F_19 Arithmetic Error / Register overflow | Cause: Indexer Program generated a value too large for the requested register. Remedy: Review variable types and math operations in the program. |
| F_20 Subroutine stack overflow | Cause: Exceeded 32 levels of subroutine stack depth (excessive calls without RETURN). Remedy: Verify program logic to ensure all calls have corresponding RETURN statements. |
| F_25 Unknown opcode | Cause: Byte code interpreter error; missing END statement or corrupted EPM data. Remedy: Re-download the program or replace the EPM. |
| F_27 Drive disabled | Cause: Attempt to execute motion while the drive is disabled. Remedy: Enable the drive before commanding motion in the program. |
| F_32 Positive Limit Switch | Cause: Positive limit switch is activated. Remedy: Move the axis in the negative direction or check the switch wiring. |
| F_36 Drive Disabled by User at Enable Input | Cause: Drive is disabled during operation or attempt to enable without deactivating “Inhibit”. Remedy: Check the state of the hardware Enable and Inhibit inputs. |
| F_45 2nd Encoder Position Error | Cause: Second encoder position error has exceeded maximum value. Remedy: Check the secondary encoder alignment and wiring. |