Parker AC890 Drive Fault Codes

Troubleshooting a Parker SSD AC890 system drive? View the complete reference guide for Trip messages, Safe Torque Off (STO) diagnostics, and FAQ to minimize downtime.

Parker AC890 Fault Codes Reference Table

Use the search bar in the table below to quickly find your specific error message.

Fault Code	Cause & Solution
DCHI OVERVOLTAGE	Cause: The drive internal dc link voltage is too high Solution: - The supply voltage is too high - Trying to decelerate a large inertia load too quickly - The brake resistor is open circuit
DCLO UNDERVOLTAGE	Cause: The drive internal dc link voltage is too low. Solution: - The supply voltage is too low - The supply has been lost - A supply phase is missing
OC OVERCURRENT	Cause: The motor current being drawn from the drive is too high Solution: - Trying to accelerate a large inertia load too quickly - Trying to decelerate a large inertia load too quickly - Application of shock load to motor - Short circuit between motor phases - Short circuit between motor phase and earth - Motor output cables too long or too many parallel motors connected to the drive - Fixed or auto boost levels are set too high
STO SAFE TORQUE OFF	Cause: Safe Torque Off (STO) is active. Solution: - One or both STO user inputs is low - A fault has been detected in the STO circuit
HOT HEATSINK	Cause: The drive heatsink temperature is too high Solution: - The ambient air temperature is too high - Poor ventilation or spacing between drives
ET EXTERNAL TRIP	Cause: User trip caused via control terminals. Solution: - +24V not present on external trip (terminal X15/05) - Check setting of EXT TRIP MODE parameter
IN 1 INPUT 1 BREAK	Cause: I/O TRIPS:: INPUT 1 BREAK has gone True. Solution: - Check configuration to determine source of signal
IN 2 INPUT 2 BREAK	Cause: I/O TRIPS:: INPUT 2 BREAK has gone True. Solution: - Check configuration to determine source of signal
STLL MOTOR STALLED	Cause: The motor has stalled (not rotating). Solution: - Motor loading too great - Current limit level is set too low - Stall trip duration is set too low - Fixed or auto boost levels are set too high
IT INVERSE TIME	The inverse time current limit is active: motor loading is too great; fixed or auto boost levels are too high (Full Load Current = 150% for 60 seconds).
DB R BRAKE RESISTOR	Cause: External dynamic braking resistor has been overloaded. Solution: - Trying to decelerate a large inertia load too quickly or too often
DB S BRAKE SWITCH	Cause: Internal dynamic braking switch has been overloaded. Solution: - Trying to decelerate a large inertia load too quickly or too often.
DISP OP STATION	Cause: Keypad has been disconnected from drive whilst drive is running in local control Solution: - Keypad accidentally disconnected from drive
SCI COMMS BREAK	COMMS BREAK parameter set to True (refer to I/O TRIPS menu at level 3)
CNTC CONTACTOR FBK	The CONTACTOR CLOSED input in the SEQUENCING LOGIC function block remained FALSE after a run command was issued.
SPD SPEED FEEDBACK	SPEED ERROR > 50.00% for 10 seconds.
AOT AMBIENT TEMP	The ambient temperature in the drive is too high.
OT MOTOR OVERTEMP	Cause: The motor temperature is too high. Solution: - Excessive load - Motor voltage rating incorrect - FIXED BOOST and/or AUTO BOOST set too high - Prolonged operation of the motor at low speed without forced cooling - Check setting of INVERT THERMIST parameter in I/O TRIPS menu at level 3. - Break in motor thermistor connection
I HI CURRENT LIMIT	Cause: V/Hz mode only- If the current exceeds 180% of induction stack rated current for a period of 1 second, the drive will trip. This is caused by shock loads. Solution: - Remove the cause of the shock load.
A24SC 24V FAILURE	Cause: The 24V customer output has fallen below 17V Solution: - 24V customer output is short circuited - Excessive loading
LSPD LOW SPEED OVER I	Cause: The motor is drawing too much current (>100%) at zero output frequency. Solution: - FIXED BOOST and/or AUTO BOOST set too high (refer to FLUXING menu at level 3).
PHAS PHASE FAIL	One or more input phases not present.
ENC 1 FBK ENCODER FAIL	Encoder fault
SHRT DESAT (OVER I)	Instantaneous overcurrent. Refer to OVERCURRENT in this table.
DCRP VDC RIPPLE	Cause: The dc link ripple voltage is too high. Solution: - Check for a missing input phase.
DBSC BRAKE SHORT CCT	Cause: Brake resistor overcurrent Solution: - Check brake resistance is not less than minimum value allowed - check wiring and brake resistor for earth faults
OSPD OVERSPEED	Speed feedback > 150% for 0.1 seconds.
ANIN ANALOG INPUT ERR	4-20mA analog input current > 22mA could damage the input circuit.
DBCT INT DB RESISTOR	1. Braking mode set to INTERNAL (future use only). - Set to EXTERNAL and connect an External Braking Resistor if braking is required.
TRIP UNKNOWN	An unknown trip - refer to Parker Hannifin Manufacturing
TR32 OTHER	Refer to OTHER in Appendix D: TRIPS STATUS. One or more trips have occurred with a Value greater than 32. See the list.
ATN1 MAX SPEED LOW	During Autotune the motor is required to run at the nameplate speed o f the motor. If MAX SPEED RPM limits the speed to less than this value, an error will be reported. - Increase the value of MAX SPEED RPM up to the nameplate rpm of the motor (as a minimum). - It may be reduced, if required, after the Autotune is complete.
ATN2 MAINS VOLTS LOW	The mains input voltage is not sufficient to carry out the Autotune. - Re-try when the mains have recovered.
ATN 3 NOT AT SPEED	The motor was unable to reach the required speed to carry out the Autotune. - Possible reasons include: motor shaft not free to turn; the motor data is incorrect
ATN4 MAG CURRENT FAIL	It was not possible to find a suitable value of magnetising current to achieve the required operating condition for the motor. - Check the motor data is correct, especially nameplate rpm and motor volts. - Also check that the motor is correctly rated for the drive.
ATN5 NEGATIVE SLIP F	Autotune has calculated a negative slip frequency, which is not valid. - Nameplate rpm may have been set to a value higher than the base speed of the motor. - Check nameplate rpm, base frequency, and pole pairs are correct.
ATN6 TR TOO LARGE	Cause: The calculated value of rotor time constant is too large. Solution: Check the value of nameplate rpm.
ATN7 TR TOO SMALL	Cause: The calculated value of rotor time constant is too small. Solution: Check the value of nameplate rpm.
ATN8 MAX RPM DATA ERR	Cause & Solution: This error is reported when the MAX SPEED RPM is set to a value outside the range for which Autotune has gathered data. Autotune gathers data on the motor characteristics up to 30% beyond “max speed rpm”. - If MAX SPEED RPM is later increased beyond this range, the drive had no data for this new operating area, and so will report an error. - To run the motor beyond this point it is necessary to re-autotune with MAX SPEED RPM set to a higher value.
STAC STACK TRIP	The drive was unable to distinguish between an overcurrent/desat or overvoltage trip.
ATNA LEAKGE L TIMEOUT	Cause: The leakage inductance measurement requires a test current to be inserted into the motor. It has not been possible to achieve the required level of current. Solution: - Check that the motor is wired correctly.
PLOS POWER LOSS STOP	Power Loss Stop sequence has ramped Speed Setpoint to zero or timed out.
ATNC MOTR TURNING ERR	The motor must be stationary when starting the Autotune.
ATND MOTR STALLED ERR	The motor must be able to rotate during Autotune.
ATNE AT TORQ LIM ERR	The motor is in torque limit during Autotune.
ECAL FBK ENCODR CAL	Cause: The drive has failed to set absolute position Solution: - Check the encoder supports absolute position, and that the encoder is wired correctly.
GEAR OUTPUT GBX ERROR	A non-unity output gearbox is not supported if the encoder direction is reversed.
APP APP HALTED	The application has been halted by the DSE Configuration Tool.
AERR APP ERROR	The application has ceased execution due to an error.
FERR FIRMWARE ERROR	The firmware in the drive has stopped executing.
RSLV RESOLVER ERROR	See function block description - Resolver disconnected - Resolver incorrectly wired - Resolver not compatible with resolver feedback option board - Resolver length cable too long - Incorrect Resolver Function Block settings
MI2T I2T MOTOR TRIP	See function block description - Motor is undersized.
STO SAFE TORQUE OFF	The safe torque off feature has been activated.
REFC REF ENCODER CAL	Cause: The drive has failed to set absolute position. Solution: - Check the encoder supports absolute position, and that the encoder is wired correctly.
REFF REF ENCODER FAIL	Function not implemented.
DCFG DRIVE CONFIG ERR	Cause: Drive configuration error. Solution: The configuration defined in DRIVE CONFIG doesn't match the actual drive configuration.
CT1 CUST TRIP 1	See function block description.
CT2 CUST TRIP 2	See function block description.
CT3 CUST TRIP 3	See function block description.
CT4 CUST TRIP 4	See function block description.
CT5 CUST TRIP 5	See function block description.
CT6 CUST TRIP 6	See function block description.
CT7 CUST TRIP 7	See function block description.
DCHI OVERVOLTAGE	Cause: The shared dc link voltage is too high. Solution: - The supply voltage is too high - Trying to decelerate a large inertia load too quickly - The brake resistor is open circuit
OC OVERCURRENT	The current being drawn from the drive is too high.
HOT HEATSINK	The heatsink temperature is too high.
IT INVERSE TIME	High output current for prolonged period, (warning only).
DISP DISPLAY KEYPAD	Keypad has been disconnected from drive whilst drive is running in local control Loose connection to display.
SCI LOST COMMS	Not used Refer to Parker Hannifin technical support.
T 6 24V FAILURE	The 24V customer output has fallen below 17V .
T 4 VOLTS SEL SWITCH	Failure to read voltage selector switch May be caused by excessive loading on ANOUT.
PHAS PHASE LOSS	Input phase missing
CHRG CHARGING	Cause: Failed to charge DC link. - Excessive capacitance on DC link - Short circuit on DC link
DCRP VDC RIPPLE	Cause: Excessive DC link ripple Solution: - Driving a reciprocating load
AOUT ANOUT FAULT	Overload on analog output.
VOLT VOLTS SELECTION	Invalid position on volts selector switch.
ENCI ENC NEEDS INIT	Cause: PMAC motor used with a relative encoder – Needs to run init once per power cycle. Solution: Relative encoder needs to be aligned with the motor back EMF. Use MOT POLARISATION feature to align.
COMMS FAULT CODE N	The drive has not responded to a message from the 6901 - Drive CPU busy.
COMMS FAULT CODE C	Incorrect reply from drive following a selection (command) message from the 6901. - Unexpected, due to electrical interference.
COMMS FAULT CODE P	Parity error in message received from the drive by the 6901 - Unexpected, due to electrical interference.
COMMS FAULT CODE F	Format of message received from the drive by the 6901 is incorrect - Unexpected, due to electrical interference.
COMMS FAULT CODE B	BCC (block check character) in message received from the drive by the 6901 is incorrect - Unexpected, due to electrical interference.
COMMS FAULT CODE L	Length of message received from the drive by the 6901 is incorrect (too many characters) - Unexpected, due to electrical interference
RUNTIME ALERT XXXX	Runtime alert
SAVING SAVE	SAVING SAVE- Saving to flash
LOADING LOAD	LOADING LOAD- Loading from flash.
LIMIT REACHED	LIMIT REACHED- HI High or low limit reached while editing.
KEY INACTIVE RUN FORWARD TRUE	Can’t switch to remote mode.
KEY INACTIVE RUN REV TRUE	Can’t switch to remote mode.
KEY INACTIVE JOG TRUE	JOG Can’t switch to remote mode.
KEY INACTIVE REMOTE SEQ	SEQ Run-Jog and direction keys inactive.
KEY INACTIVE REMOTE REF	REF- Direction key inactive.
KEY INACTIVE DRIVE RUNNING	RUN- Local/Remote and Jog keys inactive.
KEY INACTIVE COAST STOP FALSE  STOP-  Run	Run and Jog keys over ridden.
KEY INACTIVE ENABLE FALSE	ENBL- Run and Jog keys over ridden
CONFIG MODE FAILED ERR1	Unable to enter configuration mode.
KEY INACTIVE READ ONLY READ	Can’t edit read-only parameters
KEY INACTIVE PARAMETER LINKED READ	Obsolete message
PASSWORD LOCKED PASS	Incorrect password entered Password activated, (by pressing E key at the top of the MMI tree)
CHECKSUM FAIL DEFAULTS LOADED ERR2	Error reading data on power-up.
NEW PCODE FAILED FAIL	Failed to save new product code or country data.
DEFAULTS LOADED DATA	Loaded default fixed parameters.
KEY INACTIVE NO FREE LINKS ERR3	Obsolete message
KEY INACTIVE LOCKED ERR4	Obsolete message
QUADRATIC TORQUE UP TO CONFIRM ND	Validate change to quadratic torque mode.
CONSTANT TORQUE UP TO CONFIRM HD	Validate change to constant torque mode.
USING BACKUP APPLICATION ERR5	Failed to load most recently save application, using previous copy. This applies to: Fixed parameter file, (APP.CFG) Fixed motor data file, (MOTOR1.MOT) Fixed persistent data file, (APP.PST) Default frequency and language file, (COUNTRY.SYS) Drive ID file, (DRIVE_ID.SYS), now obsolete.
NEW PCODE SUCCESS CODE	Saved new product code.
CONFIG MODE LOCKED CONF	Exiting configuration mode.
FILE SYSTEM CORRUPT FILE	The file store is corrupted. All saved files are lost.
USING BACKUP POWER DATA CODE	At least one copy of the stack eeprom data has been corrupted.
POWER DATA CORRUPT CODE	All  copies of the stack eeprom data have been corrupted.
NEW POWER DATA DEFAULTS LOADED CODE	Power board data on the control board does not match that on the stack eeprom.
LANGUAGE DEFAULTS LOADED LANG	Default language and frequency settings lost.
USING BACKUP LANGUAGE LANG	Obsolete message
APPLICATION NOT FOUND DATA	Attempt to save fixed parameter set before it is valid.
AUTOTUNE IN PROGRESS ATN
OPERATOR OPER	Alert displayed while changing to the operator menu on pressing the PROG key.
DIAGNOSTIC DIAG	Alert displayed while changing to the diagnostic menu on pressing the PROG key.
QUICK SETUP SET	Alert displayed while changing to the quick setup menu on pressing the PROG key.
SETUP PAR	Alert displayed while changing to the setup menu on pressing the PROG key.
SYSTEM SYS	Alert displayed while changing to the system menu on pressing the PROG key
SUPER USER TRUE SUPR	Reserved for Parker Hannifin Manufacturing.
INCOMPATIBLE POWER BOARD ERR6	Power board 500v and/or underlap signals incompatible with selected product code.
CALIBRATION CHECKSUM FAIL CAL	The control board calibration data is invalid.
INCOMPATIBLE PCB PCB	Software is not compatible with this version of control card PCB.
INCOMPATIBLE POWER BOARD TYPE TYPE	Stack has been marked as a 650 or Baldor stack
NCOMPATIBLE EEPROM FLAGS FLGS	Reserved flags in stack eeprom are not zero. See comms command ri.
INCOMPATIBLE POWER BOARD CODE CODE	Product code not compatible with this version of software.
KEY INACTIVE PRE	Alert shown when the RUN key is pressed when the Pre-charge relay is still open. This implies that the DC Link voltage is below the under-voltage trip level.
INCOMPATIBLE STO TEST RECORD STO	The internal record confirming that the STO feature is tested has become corrupted.
LOCKED STO TEST RECORD STO	The control card is incompatible with the power stack STO feature.

 

How to Read AC890 Faults via DSE Lite

To get the most accurate diagnostic data in 2026, connect your PC to the drive using the Parker DSE Lite (Drive System Explorer) software. This is essential for the AC890, especially when diagnosing complex system applications.

• System Status (STO): The AC890 features Safe Torque Off. In DSE Lite, check the “Trips” folder to distinguish between a standard hardware fault and an STO safety trip (often indicated as “STO TRIP” or specific Safe Loop open statuses).
• Chart & Oscilloscope: Use the “Command” window in DSE Lite to open the software oscilloscope. This allows you to monitor the DC Bus voltage and Torque Current loop millisecond-by-millisecond leading up to a trip.
• Get Info: Using the “Module Info” or “Get Info” command in DSE Lite extracts the exact firmware version and active status words, which is critical when contacting technical support.

Frequently Asked Questions (FAQ)

Q: What does “STO TRIP” mean on an AC890?

A: “STO TRIP” indicates that the Safe Torque Off safety circuit has been opened. This is not necessarily a drive failure but a safety state. Ensure that your safety relays, E-Stops, and 24V inputs to terminals X11 (STO A and STO B) are correctly applied before attempting a reset.

Q: How do I reset a Parker AC890 fault?

A: For standard faults, press the STOP/RESET button on the keypad (red button). For remote operation, toggle the specific digital input programmed for “Trip Reset” or send a reset control word via the fieldbus (Firewire, Profibus, EtherCAT, etc.).

Q: Where is the fault history stored?

A: You can view the history via the keypad under System > Diagnostics > Trip History. This log retains the last 10 trips. If using DSE Lite, you can view the active “First Trip” tag to see what event initiated a cascade of system alarms.