Fuji Alpha 7 Servo Drive

Fault Code and MeaningCause and Remedy

OC01 / OC02


Overcurrent

(Display: oc 01 / oc 02)


The output current of the servo amplifier exceeds the rated value.

OC01: Direct detection
OC02: Indirect detection


Cause:


  • Wrong servomotor output wiring.

  • Short circuit or grounding fault in servomotor output wiring.

  • Servomotor insulation fault.

  • Failure of servomotor.

  • Incorrect resistance of braking resistor.

  • Current imbalance caused by an encoder fault.

  • Unconnected grounding cable.




Remedy:


  • Correct the wiring of power cables (U, V and W).

  • Check cables visually or through continuity check and replace the defective cable.

  • Measure the insulation resistance (Several MΩ or over to ground).

  • Measure the resistance across cables (Several Ω between cables).

  • Replace with the braking resistor within the rating.

  • Replace the servomotor.

  • Connect the grounding cable.



oS


Overspeed

(Display: oS)


The rotation speed of the servomotor exceeds 1.1 times the maximum speed.

Cause:


  • Wrong servomotor output wiring.

  • The rotation speed of the servomotor overshoots.




Remedy:


  • Correct the wiring of power cables (U, V and W).

  • Check the speed waveform during acceleration with the PC Loader. Take the following countermeasures:

    • Increase PA1_37 (acceleration time).

    • Increase PA1_52 (S-curve time constant).

    • Increase PA1_56 (speed loop gain 1).





Lu / cn


Control Power Undervoltage

(Display: Lu cn)


The voltage of the control power supplied to the servo amplifier temporarily drops below the minimum specification limit.

Cause:


  • The source voltage drops due to momentary power failure or similar.

  • Poor power supply capacity of transformer, etc.




Remedy:


  • Check the power supply environment for momentary power failure and improve the environment.

  • Check and improve the power supply capacity and transformer capacity.

  • Replace the transformer, etc.



Hu


Overvoltage

(Display: Hu)


The DC voltage inside the servo amplifier exceeds the upper limit (approx 420V).

Cause:


  • The source voltage is too high (immediately after power-on).

  • Unconnected internal regenerative resistor.

  • The regenerative energy is high.

  • Unconnected external braking resistor or wrong wiring.

  • Broken braking transistor.




Remedy:


  • Check if the source voltage is within the specification limits.

  • Insert a reactor if there is a power factor improvement capacitor.

  • Check the short-circuit wire between the RB2 and RB3 terminals.

  • Use an external regenerative resistor.

  • Connect the external braking resistor and correct its wiring.

  • Replace the servo amplifier.



Et01 / Et02


Encoder Trouble

(Display: Et 01 / Et 02)


There is a fault in the encoder built in the servomotor.

Et01: Single revolution position detection fault
Et02: Encoder memory data reading fault


Cause:


  • Fault in data sent from encoder.

  • Failure of encoder.




Remedy:


  • Use shielded cables to eliminate noise effects.

  • Replace the servomotor.



dE


Memory Error

(Display: dE)


The parameter data stored in the servo amplifier is damaged.

Cause:


  • Failure of stored data.

  • The parameter overwriting frequency has exceeded 100,000 cycles.

  • The servo-on is turned on without turning the power off and then on after the parameter was initialized.




Remedy:


  • Using the PC Loader, read parameters and enter those indicated in red.

  • Initialize parameters.

  • Turn the power off then on again. If restoration is not obtained, replace the servo amplifier.

  • Replace the servo amplifier (if overwrite limit exceeded).

  • Supply the power again.



cE


Motor Combination Error

(Display: cE)


The capacity and model of the servo amplifier do not agree with those of the connected servomotor.

Cause:


  • The capacity and model of the servo amplifier do not agree with those of the servomotor.




Remedy:


  • Check the capacity and model of the servomotor and those of the servo amplifier.



Ec


Encoder Communication Error

(Display: Ec)


Communications with the internal encoder of the servomotor fails.

Cause:


  • Interrupted encoder communications.

  • Broken wire or poor contact.

  • Noise interference (route cable near magnetic fields).




Remedy:


  • Check cables visually and through continuity check and correct faults.

  • Check for the broken wire in the encoder cable and correct.

  • Insert ferrite cores.

  • Do not route the encoder cable in a strong magnetic or electric field. Route separately from power lines.



co nt


CONT (control signal) Error

(Display: co nt)


There is duplication in allocation of sequence input terminals of the servo amplifier.

Cause:


  • The same input signal is allocated to two or more terminals.




Remedy:


  • Do not specify the same number among CONT signal settings.


oL 01 / oL 02

Overload
(Instantaneous alarm or Effective torque exceeds limit)

Cause:

  • The servomotor fails to rotate mechanically.

  • The mechanical system is too heavy against the servomotor capacity.

  • The acceleration/deceleration frequency and operation frequency are too high.

  • Servo amplifier is damaged.




Remedy:

  • Check if the brake is active.

  • Examine the servomotor capacity, based on the load factor.

  • If rotation speed can be reduced, add a reduction gear.

  • Apply the brake to retain a stopped elevator.

  • Increase the cycle time and decrease the operation frequency.

  • Replace the servo amplifier.

  • If OL02 occurs without damage/wiring issues, examine servomotor capacity.


rH 04

Inrush Current Suppression Circuit Trouble

Cause:

  • The servo amplifier is damaged.

  • The ambient temperature exceeds 55°C.

  • The power is frequently supplied.




Remedy:

  • Replace the servo amplifier.

  • Keep the ambient temperature 55°C or lower (40°C or below is recommended).

  • Move heat generating bodies near the servo amplifier as far away as possible.

  • Reduce the frequency of turning the power on/off (Reference: once an hour or less).

  • Note: If detected when temp is below 55°C, replace amplifier.


SF tY

Safety function error

Cause:

  • The [EN1+], [EN2+] terminal input mismatch continued for 50 ms or longer.

  • The function safety module (WSU-ST1) output an alarm.

  • A servo amplifier or function safety module (WSU-ST1) fault occurred.




Remedy:

  • Check for wiring abnormalities such as disconnection or shorting in the [EN1+], [EN2+] terminal wiring.

  • Reduce the [EN1+], [EN2+] terminal input mismatch time to 50 ms or less.

  • Refer to the function safety module (WSU-ST1) User’s Manual.

  • Turn power OFF/ON. If not resolved, replace servo amplifier or safety module.

  • Check the function safety module mounting condition.


Lu Po

Main Power Undervoltage

Cause:

  • The source voltage drops due to momentary power failure or similar.

  • The power is turned on or off intentionally.

  • DC input is under execution.




Remedy:

  • Check the power supply environment (momentary failure) and improve capacity/transformer.

  • Do not turn the power on after the time specified in PA2_68 has elapsed.

  • Set PA2_68 (main power shutoff detection time) at 1000 [ms].

  • If environment is adverse, PA2_67 can be applied to ignore undervoltage detection.


rH 01

Internal Braking Resistor Overheat

Cause:

  • Excessive source voltage (immediately after power-on).

  • Due to vertical transfer or winding purpose, regenerative power cannot be consumed.




Remedy:

  • Check if the source voltage is within specification limits.

  • Insert a reactor if there is a power factor improvement capacitor.

  • Increase the deceleration time.

  • Decrease the servomotor rotation speed.

  • Increase the cycle time and decrease the operation frequency.

  • Connect an external braking resistor.

  • Install a counterweight.


rH 02

External Braking Resistor Overheat

Cause:

  • Excessive source voltage (immediately after power-on).

  • Due to vertical transfer or winding purpose, regenerative power cannot be consumed.

  • Wrong wiring of external braking resistor overheat signal.




Remedy:

  • Check if the source voltage is within the specification limits.

  • Increase the deceleration time.

  • Decrease the servomotor rotation speed.

  • Increase the cycle time and decrease the operation frequency.

  • Connect an external braking resistor or install a counterweight.

  • Connect the wiring correctly.


rH 03

Braking Transistor Error

Cause:

  • The braking transistor is short circuited or damaged.




Remedy:

  • Turn the power off then on again. If the alarm persists, replace the servo amplifier.

  • Note: If short circuited/damaged, fire may be caused. Turn power off immediately.


oF
Deviation Overflow

Cause: Wrong connection of power cables; Servomotor mechanically locked; Low output torque; Deviation detection width is small; Amplifier is in P control mode; Low gain; Rapid acceleration/deceleration; External pulse phase mismatch.



Remedy:

  • Check and correct the wiring of power cables (U, V and W).

  • Check if the brake is applied.

  • Increase torque limit values (PA1_27 and 28).

  • Increase the deviation overflow detection value (PA2_69) or External/Motor deviation over detection value (PA4_36).

  • Turn off the P motion signal.

  • Perform gain adjustment.

  • Increase the acceleration/deceleration time.

  • Check the set value of PA4_32 (external pulse phase selection).


AH
Amplifier Overheat

Cause: The ambient temperature exceeds 55 [°C]; Heat generating bodies are too close.



Remedy:

  • Reduce the ambient temperature to 55 [°C] or lower (40 [°C] recommended).

  • Move heat generating bodies near the servo amplifier as far away as possible.

  • Perform operation at a continuous load factor within 100%.


EH
Encoder Overheat

Cause: Excessive ambient temperature; The effective torque exceeds the rating.



Remedy:

  • Reduce the ambient temperature of the servomotor to 40 [°C] or lower.

  • Remove shields interrupting heat radiation, if there are any.

  • Increase the cycle time and reduce the operation frequency.


dL 01 / dL 02 / dL 03
Absolute Data Lost

Cause:

dL01: Battery voltage drop, broken cable.

dL02: Multi-turn data fault in encoder.

dL03: Detection at power-on after an Et alarm.



Remedy:

  • dL01: Replace the battery and preset the position. Check if encoder cable is broken.

  • dL02: Perform position preset. If the alarm persists, replace the servomotor.

  • dL03: Perform position preset. If the Et alarm is not canceled, replace the servomotor.


AF
Multi-turn Data Overflow

Cause: Excessive servomotor revolutions (Output shaft exceeds range between -32766 and +32765).



Remedy:

  • Check the servomotor revolutions.

  • Use the PC Loader or take similar measures to check the current position.


iE
Initial Error

Cause: The encoder is damaged; Power turned on while the servomotor rotates on external force.



Remedy:

  • Replace the servomotor.

  • Stop the servomotor and turn the power off then on again. If restoration is not obtained, replace the servomotor.


HF
Command Pulse Frequency Error

Cause: Gear Ratio was changed; The set value of pulse such as electronic gear setting is large.



Remedy:

  • Review the master processing.

  • Set the ratio of pulses to an appropriate setting value.


oL 03
Overload 3 (Output open-phase)

Cause: The servomotor fails to rotate mechanically.



Remedy:

  • Check the wiring of power cables (U, V and W) and correct faults.


cY
Cycle communication error

Cause: An error occurred during EtherCAT communication.



Remedy:

  • Check the condition of the communication cable (disconnection, etc.), and fix if necessary.

  • Insert a ferrite core into the communication cable.

  • Adjust the interval between the communication timing and DC timing.

  • Check whether the ESM State is other than OP with servo-on.