Troubleshooting

Source: 04.ES750N_故障处理.html (the “Troubleshooting” chapter of the ES750N series servo-drive manual)

Restart after a fault

Stage	Action	Notes
When the fault occurs	View the last three fault timestamps, types, and the frequency/current/bus/DI/DO state at the time of fault on the operator panel	Use `F9-18`–`F9-44`
Before reset	Identify and clear the cause from the fault code on the panel, then reset	Refer to the fault-code list for handling

Fault reset

DI reset: set a DI to function 9 (F4-00–F4-04=9, fault reset) and drive it active.
Panel reset: confirm F7-02=2 (factory default); the red stop/reset key on the panel resets faults in any operating mode.
Power-cycle reset: disconnect main power, wait until the panel display disappears, then reapply power for automatic reset.
Communication reset: from the host, write “7” (fault reset) to address 2000H to reset after the fault is cleared.

⚠️

Some faults require the cause to be cleared by a setting change before reset, but a successful reset does not mean the change is in effect. Changes that require a power-cycle must be followed by a power-cycle.

Common symptoms and remedies

No.	Symptom	Possible cause	Remedy
1	No display on power-up	Grid voltage missing or too low	Check input power
		Drive-board switch-mode supply faulty	Check bus voltage
		Control-board, drive-board, or keypad cable broken	Reseat the 64-pin cable
		Buffer resistor damaged / control board or keypad faulty	Consult a technician
		Rectifier damaged / poor contact between drive and control boards	Reseat the 64-pin cable
2	Display continuously shows “HC” on power-up	Components on the control board damaged / motor or motor cable grounded / Hall fault	Consult a technician
3	Shows “HC” and stops immediately after running	Fan damaged or stalled	Replace fan
		External control terminal wiring shorted	Clear the external short
		Motor wiring abnormal	Re-verify the drive-to-motor wiring
4	Motor does not rotate after the drive runs	Drive parameter error (motor params)	Restore factory settings and reconfigure; verify `F0-01` (control mode) and `F0-02` (run mode)
		Poor contact between drive and control boards	Reseat the connection
		Drive-board fault	Consult a technician
5	DI terminal not effective	Parameter error	Recheck F4-group parameters
		Wrong external signal	Rewire the external signal
		Wrong S5 DIP setting	Confirm S5 matches actual wiring
		Control-board fault	Consult a technician
6	In closed-loop vector, motor speed cannot increase	Encoder fault / wrong or loose encoder wiring / PG-card fault	Replace the encoder and re-verify wiring; replace the PG card; consult a technician
7	Drive frequently reports overcurrent and overvoltage	Motor parameters incorrect	Reconfigure motor parameters or run motor identification
		Acceleration/deceleration time inappropriate	Set appropriate acceleration/deceleration times
		Load fluctuation	Consult a technician
8	Motor coasts during deceleration or cannot brake	Encoder open or overvoltage-stall protection triggered	Check encoder wiring; if a braking resistor is installed, set `F3-23=0` to disable overvoltage stall
9	Burnt buffer resistor	Braking-resistor lead shorted to chassis / braking transistor blown / bus capacitor blown/shorted / negative bus to ground	Add insulation / replace braking transistor / replace bus capacitor / clear the short

Fault-code list

E002.0: hardware overcurrent

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Axis 1: instantaneous output current exceeds 2.5 × 1.414 × rated current. Axis 2: exceeds 2 × 1.414 × rated.

Cause	Verification	Remedy
Drive-board abnormal	Check for proper grounding and lack of interference; check encoder speed feedback	Replace components causing grounding issues; try replacing the encoder and cable

E002.2: software overcurrent

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Instantaneous output current exceeds the software overcurrent point

Cause	Verification	Remedy
Drive output ground or short circuit	Check for motor or contactor short	Replace components causing grounding issues
Encoder interference or disconnection, or encoder loose/reversed/poor-concentricity causing oscillation overcurrent	Check encoder	Tune `F8-43` encoder interference threshold; try replacing encoder and cable
FVC/SVC without parameter identification	Set motor parameters from nameplate and identify	Run motor-parameter identification
Acceleration time too short	Check `F0-17`	Increase acceleration time (`F0-17`)
Overcurrent stall-suppression settings inappropriate	Check `F3-19` enable, `F3-18` action current, `F3-20` gain	Confirm enable; recommend `F3-18` 120%–160%; recommend `F3-20` 20–40

E005.0: overvoltage

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	1. Motor generating, regenerative energy raises the bus voltage. 2. Input voltage abnormal.

Cause	Verification	Remedy
Input grid voltage high	Measure with a multimeter	Adjust voltage to normal
Ground short	Check ground impedance	Clear the ground short
Encoder open or poor concentricity causing oscillation overvoltage	Check encoder	Replace encoder and cable
Coasting from overspeed on a PMSM causes high back-EMF	Check feedback speed via host software	Limit max speed or add safety measures
Weak speed loop (acceleration too fast) causes overshoot overvoltage	Check for speed overshoot	Increase `F0-17`; enable torque feedforward and RFG arc
External force driving the motor during acceleration	Check for external force	Remove the external force
No braking unit or resistor installed	Check for braking unit and resistor	Install

E008.0: buffer-resistor fault

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Counter detects 5 abnormal bus-voltage fluctuations within a set period

Cause	Verification	Remedy
Contactor abnormal or frequent rapid power cycles	Confirm input is 342 V AC–418 V AC; confirm no repeated power cycles	Contact technical support

E009.1: undervoltage

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	1. Contactor not engaged. 2. Input voltage abnormal, bus voltage below the undervoltage point.

Cause	Verification	Remedy
Momentary power loss	Confirm input is 342 V AC–418 V AC	Enable the “ride-through” function (`F9-59`)
Drive input voltage out of range	Measure input voltage	Adjust voltage to normal
Input phase loss	Measure input grid voltage; check rectifier diodes	Clear phase loss
Bus voltage abnormal	Use host software to capture bus voltage	Contact technical support
Rectifier or inverter drive board abnormal	Confirm DC bus voltage with a multimeter	Contact technical support

E009.3: pre-drive timeout

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	In an undervoltage state, the bus-voltage ramp-up after motor start did not complete within 5 s

Cause	Verification	Remedy
Pre-charge abnormal; start in undervoltage	Confirm bus voltage is normal (≈1.414 × input RMS)	Wait for the bus to stabilize; check the main contactor/grid

E010.0: drive overload

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Judged by the drive overload curve

Cause	Verification	Remedy
Load too large or motor stalled	Check output current and for motor stall	Reduce load and check the mechanics
Drive undersized	Confirm drive power is less than motor power	Use a higher-power drive
FVC/SVC without parameter identification	Check identification	Set nameplate parameters and run identification
Encoder abnormal	Check encoder	Try replacing encoder and cable
Synchronous motor demagnetized	Measure back-EMF	Replace the motor
Input voltage low causing high output current	Confirm input is 342 V AC–418 V AC	Raise input voltage

E011.0: motor overload

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Judged by the motor overload curve

Cause	Verification	Remedy
Motor-protection parameter `F9-01` inappropriate	Check `F9-01`	Set correctly; raising `F9-01` extends motor overload time
Load too large or motor stalled	Check output current; check for stall	Reduce load and check the mechanics

E012.0: input phase loss

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Hardware signal indicates input phase loss

Cause	Verification	Remedy
Input phase loss	Check RST wiring and that the three-phase input voltage is normal	Fix RST wiring and ensure three-phase input is normal

E013.0: output phase loss

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Above 0.8 Hz, the max/min ratio of three-phase output current averages exceeds 10×

Cause	Verification	Remedy
System output phase loss	Check for output phase loss	Contact technical support

E013.1 / E013.2 / E013.3: U/V/W phase output phase loss

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Above 0.8 Hz, the max/min ratio of three-phase output current averages exceeds 10× and the corresponding phase is the minimum

Cause	Verification	Remedy
Motor fault	Check that phase for open circuit	Repair or replace the motor
Drive-to-motor cable abnormal	Check wiring	Fix external fault
Three-phase output unbalanced	Check three-phase output RMS current	Inspect windings and fix
Drive board or IGBT abnormal	Other causes cleared but fault persists	Contact technical support
Output contactor fault or tripped	Check the output contactor	Replace the output contactor

E014.0: drive overheat

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Heatsink temperature above the overtemperature point

Cause	Verification	Remedy
Ambient too high	Check ambient temperature	Lower ambient
Air duct blocked	Check duct	Clear duct
Fan damaged	Check fan	Replace fan
Module thermistor damaged	Stop and wait 1 h, then check temperature	Replace thermistor
Module damaged	Check for module damage	Contact technical support

E015.0: external fault

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	External terminal NC/NO fault

Cause	Verification	Remedy
External fault via multi-function DI	Check F4 parameters and DI physical state	Clear external fault, confirm mechanism can restart, reset

E016.3: Modbus communication fault

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Communication break exceeds the timeout setting

Cause	Verification	Remedy
Modbus timeout	Check RS485 wiring; check `Fd-04` and PLC cycle	Contact technical support

E017.0: contactor fault

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Hardware contactor-abnormal signal sampled continuously for 1 s

Cause	Verification	Remedy
Contactor abnormal	Confirm input is 342 V AC–418 V AC	Replace contactor

E018.0: current-detection circuit fault

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Zero-drift detection exceeds 10% of rated current

Cause	Verification	Remedy
Current-sampling abnormal	Measure three-phase UVW current at standstill; check if fluctuation exceeds 10% of rated	Check that main power is on; Hall sensor or sampling circuit damaged—contact the manufacturer

E019.1: motor-parameter identification timeout

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Identification timed out

Cause	Verification	Remedy
Identification timeout	Verify motor parameters (`F1-00`–`F1-05`) and drive-model parameter (`FF-01`) against nameplate	Set accurate nameplate values; motor may not be connected or output may have phase loss

E019.2: motor-parameter identification interrupted

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Identification was stopped before completion

Cause	Verification	Remedy
Identification interrupted	Confirm whether identification completed	Stop before completion; run identification again

E019.3: overcurrent during identification

Item	Notes
Default fault level	0: coast to stop
Resettable	Yes
Mechanism	Overcurrent during identification

The above details the common ES750N fault codes. For a more complete list (including E043.x encoder-related, E077.x communication, E093.x STO, etc.), refer to the “Fault Alarms and Remedies” chapter of the original manufacturer manual.

Fault-code quick reference

Code	Name	Resettable	Common direction
`E002.0`	Hardware overcurrent	Yes	Check grounding and encoder feedback
`E002.2`	Software overcurrent	Yes	Check for short/ground, encoder, motor identification, acceleration time
`E005.0`	Overvoltage	Yes	Check input voltage, encoder, braking resistor, acceleration time
`E008.0`	Buffer-resistor fault	Yes	Check contactor and input-power stability
`E009.1`	Undervoltage	Yes	Check input voltage, phase loss, contactor
`E009.3`	Pre-drive timeout	Yes	Wait for bus to stabilize; check power-on circuit
`E010.0`	Drive overload	Yes	Check load, drive sizing, motor identification
`E011.0`	Motor overload	Yes	Check `F9-01`, load
`E012.0`	Input phase loss	Yes	Check RST wiring and input voltage
`E013.0`	Output phase loss	Yes	Check output wiring
`E013.1`	U-phase output phase loss	Yes	Check motor U phase and cable
`E013.2`	V-phase output phase loss	Yes	Check motor V phase and cable
`E013.3`	W-phase output phase loss	Yes	Check motor W phase and cable
`E014.0`	Drive overheat	Yes	Check ambient, duct, fan
`E015.0`	External fault	Yes	Check external DI state
`E016.3`	Modbus communication fault	Yes	Check RS485 wiring and `Fd-04`
`E017.0`	Contactor fault	Yes	Check contactor and input voltage
`E018.0`	Current-detection circuit fault	Yes	Check main circuit and Hall sensor
`E019.1`	Motor-parameter identification timeout	Yes	Check motor and model parameters
`E019.2`	Motor-parameter identification interrupted	Yes	Re-run identification
`E019.3`	Overcurrent during identification	Yes	Check motor wiring and parameters

Quick Tuning Guide Parameter List