Parker AC690+ Plus Drive Fault Codes

Troubleshoot your Parker AC690+ plus system drive with our updated fault code list. Learn to interpret 6901 keypad messages, use DSE Lite, and resolve complex system trips.

Parker AC690+ Fault Codes Reference Table

Below is the complete list of trips and diagnostic messages. Note that most AC690+ units use the 6901 (LCD) keypad, which provides full-text descriptions of the fault.

690+ Series AC Drive - Trip Messages

Fault Code and Meaning	Cause and Remedy
OVERVOLTAGE The drive internal dc link voltage is too high	Cause: High voltage conditions detected. Remedy: The supply voltage is too high. Trying to decelerate a large inertia load too quickly. The brake resistor is open circuit.
UNDERVOLTAGE The drive internal dc link voltage is too low	Cause: Low voltage conditions detected. Remedy: Check if the supply voltage is too low. Check if the supply has been lost. Check if a supply phase is missing.
OVERCURRENT The motor current being drawn from the drive is too high	Cause: Current limits exceeded due to load or wiring issues. Remedy: 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.
HEATSINK The drive heatsink temperature is too high	Cause: Thermal overload of the drive unit. Remedy: The ambient air temperature is too high. Poor ventilation or spacing between drives.
EXTERNAL TRIP User trip caused via control terminals	Cause: External signal missing. Remedy: +24V not present on external trip (e.g. terminal 19, Macro 1).
INPUT 1 BREAK A signal break has been detected on analog input 1 (terminal 1)	Cause: 4-20mA signal loss detected. Remedy: Analog input is incorrectly configured for 4-20mA operation. Break in external control wiring.
INPUT 2 BREAK A signal break has been detected on analog input 2 (terminal 2)	Cause: 4-20mA signal loss detected. Remedy: Analog input is incorrectly configured for 4-20mA operation. Break in external control wiring.
MOTOR STALLED The motor has stalled (not rotating)	Cause: Motor unable to turn under load. Remedy: 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.
INVERSE TIME The inverse time current limit is active	Cause: Prolonged overcurrent condition. Remedy: Motor loading is too great: Motor current >150% for 60s in Constant duty. Motor current >110% for 60s in Quadratic duty. Fixed or autoboost levels are too high.
BRAKE RESISTOR External dynamic braking resistor has been overloaded	Cause: Excessive energy dumped to resistor. Remedy: Trying to decelerate a large inertia load too quickly or too often.
BRAKE SWITCH Internal dynamic braking switch has been overloaded	Cause: Excessive energy dumped to brake circuit. Remedy: Trying to decelerate a large inertia load too quickly or too often.
OP STATION Keypad has been disconnected from drive whilst drive is running in local control	Cause: Communication loss with HMI. Remedy: Keypad accidentally disconnected from drive.
LOST COMMS Communications Failure	Cause: Timeout detected. Remedy: COMMS TIMEOUT parameter set too short (refer to COMMS CONTROL menu at level 3).
CONTACTOR FBK Contactor Feedback Error	Cause: Logic mismatch. Remedy: The CONTACTOR CLOSED input in the SEQUENCING LOGIC function block remained FALSE after a run command was issued.
SPEED FEEDBACK Speed deviation detected	Cause: Control loop error. Remedy: SPEED ERROR > 50.00% for 10 seconds.
AMBIENT TEMP The ambient temperature in the drive is too high	Cause: Environment too hot. Remedy: Check cooling and ventilation. The ambient temperature in the drive is too high.
MOTOR OVERTEMP The motor temperature is too high	Cause: Thermal overload of the motor. Remedy: 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.
CURRENT LIMIT Current exceeds 180% of stack rated current for 1 second	Cause: Shock loads. Remedy: Remove the cause of the shock load.
24V FAILURE The 24V customer output has fallen below 17V	Cause: Overload on auxiliary supply. Remedy: 24V customer output is short circuited. Excessive loading.
TRIP 19 Reserved	Cause: Reserved. Remedy: Reserved.
LOW SPEED OVER I The motor is drawing too much current (>100%) at zero output frequency	Cause: Excessive magnetizing current. Remedy: FIXED BOOST and/or AUTO BOOST set too high (refer to FLUXING menu at level 4).
PHASE FAIL One or more phases of the 3-phase supply is missing	Cause: Input power loss. Remedy: Check supply connections. Check fuses.
ENCODER 1 FAULT Encoder Error	Cause: Encoder module signal error. Remedy: The Error input on the Encoder TB is in the Error state.
DESAT (OVER I) Instantaneous overcurrent	Cause: Hardware protection trip. Remedy: Refer to OVERCURRENT in this table.
VDC RIPPLE The dc link ripple voltage is too high	Cause: Supply imbalance. Remedy: Check for a missing input phase.
BRAKE SHORT CCT Brake resistor overcurrent	Cause: Low resistance. Remedy: Check resistance brake resistor value is greater than minimum allowed.
OVERSPEED Speed limit exceeded	Cause: Speed feedback has exceeded the THRESHOLD for a period greater than DELAY. Remedy: Check speed loop tuning. Check overspeed threshold parameters.
ANALOG INPUT ERR Analog Input Signal Error	Cause: Signal out of range. Remedy: Analog input is incorrectly configured for 4-20mA operation. Short circuit in external control wiring. Extreme over-range of remote sensor.
TRIP 29 Reserved	Cause: Reserved. Remedy: Reserved.
TRIP 30 Reserved	Cause: Reserved. Remedy: Reserved.
UNKNOWN An unknown trip	Cause: Unknown system error. Remedy: Refer to Parker SSD Drives.
MAX SPEED LOW Autotune Error: MAX SPEED RPM limits speed to less than nameplate value	Cause: Configuration error during Autotune. Remedy: 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.
MAINS VOLTS LOW The mains input voltage is not sufficient to carry out the Autotune	Cause: Supply sag during test. Remedy: Re-try when the mains has recovered.
NOT AT SPEED The motor was unable to reach the required speed to carry out the Autotune	Cause: Mechanical or Data issue. Remedy: Motor shaft not free to turn. The motor data is incorrect.
MAG CURRENT FAIL Unable to find suitable magnetising current	Cause: Motor data mismatch. Remedy: Check the motor data is correct, especially nameplate rpm and motor volts. Check that the motor is correctly rated for the drive.
NEGATIVE SLIP F Autotune has calculated a negative slip frequency	Cause: Data entry error. Remedy: 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.
TR TOO LARGE Calculated rotor time constant too large	Cause: Calculation out of bounds. Remedy: Check the value of nameplate rpm.
TR TOO SMALL Calculated rotor time constant too small	Cause: Calculation out of bounds. Remedy: Check the value of nameplate rpm.
MAX RPM DATA ERR MAX SPEED RPM is set outside range of Autotune data	Cause: Data unavailable for new speed range. Remedy: Autotune gathers data up to 30% beyond "max speed rpm". If MAX SPEED RPM is increased later, re-autotune with MAX SPEED RPM set to a higher value.
STACK TRIP Drive hardware trip	Cause: Critical hardware protection. Remedy: The drive was unable to distinguish between an overcurrent/Dsat or overvoltage trip.
LEAKGE L TIMEOUT Leakage inductance measurement timeout	Cause: Unable to achieve required test current. Remedy: Check that the motor is wired correctly.
POWER LOSS STOP Power Loss Stop sequence ended	Cause: Sequence completion. Remedy: Power Loss Stop sequence has ramped Speed Setpoint to zero or timed out.
MOTR TURNING ERR Motor moving at start of Autotune	Cause: Motor not stationary. Remedy: The motor must be stationary when starting the Autotune.
MOTR STALLED ERR Motor unable to rotate during Autotune	Cause: Mechanical blockage. Remedy: The motor must be able to rotate during Autotune.

 

How to Read Parker AC690+ Faults via DSE Lite

Because the AC690+ is often used in complex automated systems, using the Parker Drive System Explorer (DSE Lite) software is the best way to diagnose issues in 2026. This allows you to see the drive’s internal function blocks and how they interact with your PLC or other drives.

Key Diagnostic Features:

• First Trip Logic: In complex systems, one failure can trigger others. DSE Lite allows you to identify the “First Trip,” which is the actual root cause before cascading faults occurred.
• TechBox Monitoring: If your 690+ uses a TechBox for communications (Profinet, DeviceNet, etc.), DSE Lite can diagnose if a trip is being caused by a “Fieldbus Break” or a loss of communication with the master controller.
• Trip History Log: The drive maintains a rolling log of the last 10 trips. You can extract this log via the P3 port to identify patterns, such as intermittent “Heatsink Overtemp” trips occurring at specific times of day.

Frequently Asked Questions (FAQ)

Q: What is the difference between an Alarm and a Trip on the 690+?

A:

• Alarms: These appear on the display (e.g., “STALL”) to warn you that the drive is operating outside of normal limits. The drive will continue to run, but may trip if the condition persists.
• Trips: These are critical failures that immediately open the drive output and stop the motor. The display will show the trip name (e.g., “OVERCURRENT”).

Q: How do I reset a Parker AC690+ fault?

A: Once the fault is cleared, you can reset the drive by:

1. Pressing the red Stop/Reset button on the 6901 keypad.
2. Using a Digital Input programmed for “Trip Reset.”
3. Sending a “Reset” bit via your Fieldbus communication network.

Q: Why does my drive show “EXTERNAL TRIP”?

A: This indicates that a signal has been sent to a digital input configured as an External Trip. This is commonly wired to motor thermistors, emergency stop relays, or secondary safety systems. Check your external control wiring.

Q: Where is the fault history on the keypad?

A: On the 6901 keypad, navigate to DIAGNOSTICS > FIRST TRIP to see the most recent fault, or browse the trip log to see previous events.