Allen Bradley PowerFlex 70 Drive Fault Codes List

Complete guide to Allen Bradley PowerFlex 70 fault codes . Troubleshoot DPI Port faults, F75 Adapter Loss, Decel Inhibit trips, and use the HIM to access diagnostic history.

PowerFlex 70 Fault Codes Reference Table

Fault Codes	Cause & Solutions
F29 Analog In Loss	Cause: An analog input is configured to fault on signal loss. A signal loss has occurred. - Configure with [Anlg In X Loss]. Solution: - Check the parameters. - Check for broken/loose connections at inputs.
F108 Anlg Cal Chksum	Cause: The checksum read from the analog calibration data does not match the checksum that is calculated. Solution: - Replace the drive.
F33 Auto Rstrt Tries	Cause: Drive unsuccessfully attempted to reset a fault and resume running for the programmed number of [Flt RstRun Tries]. - Enable/Disable with [Fault Config 1]. Solution: - Correct the cause of the fault and manually clear.
F80 AutoTune Aborted	Cause: Autotune function was canceled by the user or a fault occurred. Solution: - Restart the procedure.
F55 Cntl Bd Overtemp	Cause: The temperature sensor on the Main Control Board detected excessive heat. Solution: - Check Main Control Board fan. - Check surrounding air temperature. - Verify proper mounting/ cooling.
F2 Auxiliary Input	Cause : Auxiliary input interlock is open. Solution: - Check remote wiring. - Verify communications programming for intentional fault.
F69 DB Resistance	Cause: The resistance of the internal DB unit is out of range. Solution: - Replace the resistor.
F24 Decel Inhibit	Cause: The drive is not following a commanded acceleration or deceleration because it is attempting to limit bus voltage. Solution: - Verify that input voltage is within drive specified limits. - Verify that system ground impedance follows proper grounding techniques. - Disable bus regulation and/or add dynamic brake resistor and/or extend deceleration time.
F64 Drive Overload	Cause: Drive rating of 110% for 1 minute or 150% for 3 seconds has been exceeded. Solution: Reduce load or extend Accel Time.
F49 Drive Powerup	No fault is displayed. Used as a Powe r Up Marker in the Fault Queue indicating that the drive power has been cycled.
F111 Enable Hardware	Cause: & solution: 1. Safe-Off board is not installed and pins 3 and 4 of the Safe-Off Connector are not jumpered. - Install Safe-Off board or jumper pins 3 and 4. 2. If Safe-Off board is installed, verify that the hardware enable jumper is removed. - Locate and remove the enable jumper on the main control board. Refer to DriveGuard Safe-Off Option (Series B) for PowerFlex 40P and PowerFlex 70 AC Drives, publication PFLEX-UM003, for instructions and location. 3. Safe-Off board has failed. - Replace Safe-Off board. 4. Hardware enable circuitry failed. - Replace control board.
F91 Encoder Loss	Cause: One or both encoder channel signals is missing. Solution: - Check Wiring. - Replace encoder.
F90 Encoder Quad Err	Cause: Both encoder channels changed state within one clock cycle. Solution: - Check for externally induced noise. - Replace encoder.
F93 Hardware Fault	Cause: Hardware enable is disabled (jumpered high) but logic pin is still low. Solution: - Check jumper. - Replace Main Control Board.
F79 Excessive Load	Cause: Motor did not come up to speed in the allotted time during autotune. Solution: - Uncouple load from motor. - Repeat Autotune.
F52 Faults Cleared	No fault displayed. Used as a marker in the Fault Queue indicating that the fault clear function was performed.
F900… F930 Fatal Faults	Cause: Diagnostic code indicating a drive malfunction. Solution: - Cycle power. - Replace Main Control Board. - Contact Tech Support.
F51 Flt QueueCleared	No fault displayed. Used as a marker in the Fault Queue indicating that the clear queue function was performed.
F78 FluxAmpsRef Rang	Cause: The value for flux amps determined by the Autotune procedure exceeds the programmed [Motor NP FLA]. Solution: - Reprogram [Motor NP FLA] with the correct motor nameplate value. - Repeat Autotune.
F13 Ground Fault	Cause: A current path to earth ground has been detected at one or more of the drive output terminals. Solution: - Check the motor and external wiring to the drive output terminals for a grounded condition.
F10 Heatsink LowTemp	Cause: Annunciates a too low temperature case or an open NTC (heatsink temperature sensing device) circuit. Solution: - Verify ambient temperature. - In cold ambient temperatures, add space heaters. - Check connections to NTC.
F8 Heatsink OvrTmp	Cause: Heatsink/Power Module temperature exceeds a predefined value. Solution: - Check for blocked or dirty heatsink fins. Verify that ambient temperature has not exceeded the rated ambient temperature. - Check fan.
F12 HW OverCurrent	Cause: The drive output current has exceeded the hardware current limit. Solution: - Check output of drive or motor for shorts. - Check programming. - Check for excess load, improper DC boost setting, DC brake volts set too high, or other causes of excess current.
F106 Incompact MCB-PB	Cause: Drive rating information that is stored on the power board is incompatible with the main control board. Solution: Load compatible version files into drive.
F17 Input Phase Loss	Cause: The DC bus ripple has exceeded a preset level. Solution: - Check incoming power for a missing phase/blown fuse.
F77 IR Volts Range	Cause: “Calculate” is the autotune default and the value that is determined by the autotune procedure for IR Drop Volts is not in the range of acceptable values. Solution: - Re-enter motor nameplate data.
F87 IXo VoltageRange	Cause: Voltage calculated for motor inductive impedance exceeds 25% of [Motor NP Volts]. Solution: - Check for proper motor sizing. - Check for correct programming of [Motor NP Volts], parameter 41. - Additional output impedance can be required.
F15 Load Loss	Cause: Drive output torque current is below [Load Loss Level] for a time period greater than [Load Loss time]. Solution: - Verify connections between motor and load. - Verify level and time requirements.
F7 Motor OverLoad	Cause: - Internal electronic overload trip. - Enable/Disable with [Fault Config 1]. Solution: - An excessive motor load exists. - Reduce load so drive output current does not exceed the current set by [Motor NP FLA]. If enabled, check level of flux braking in parameter P549 [Flux Braking %].
F16 Motor Thermistor	Cause: Thermistor output is out of range. Solution: - Verify that thermistor is connected. - Motor is overheated. Reduce load.
F25 Overspeed Limit	Cause: Functions such as Slip Compensation or Bus Regulation have attempted to add an output frequency adjustment greater than that programmed in [Overspeed Limit]. Solution: Remove excessive load or overhauling conditions or increase [Overspeed Limit].
F5 OverVoltage	Cause: DC bus voltage exceeded max value. Solution: - Monitor the AC line for high line voltage or transient conditions. - Bus overvoltage can also be caused by motor regeneration. - Extend the decel time or install dynamic brake option.
F100 Parameter Chksum	Cause: The checksum read from the board does not match the checksum calculated. Solution: - Restore defaults. - Reload User Set if used.
F48 Params Defaulted	Cause: The drive was commanded to write default values to EEPROM. Solution: - Clear the fault or cycle power to the drive. - Program the drive parameters as needed.
F38 Phase U to Gnd	Cause: A phase to ground fault has been detected between the drive and motor in this phase. Solution: - Check the wiring between the drive and motor. - Check motor for grounded phase. - Replace drive if fault cannot be cleared.
F39 Phase V to Gnd	Cause: A phase to ground fault has been detected between the drive and motor in this phase. Solution: - Check the wiring between the drive and motor. - Check motor for grounded phase. - Replace drive if fault cannot be cleared.
F40 Phase W to Gnd	Cause: A phase to ground fault has been detected between the drive and motor in this phase. Solution: - Check the wiring between the drive and motor. - Check motor for grounded phase. - Replace drive if fault cannot be cleared.
F41 Phase UV Short	Cause: Excessive current has been detected between these two output terminals. Solution: - Check the motor and drive output terminal wiring for a shorted condition. - Replace drive if fault cannot be cleared.
F42 Phase UW Short	Cause: Excessive current has been detected between these two output terminals. Solution: - Check the motor and drive output terminal wiring for a shorted condition. - Replace drive if fault cannot be cleared.
F43 Phase VW Short	Cause: Excessive current has been detected between these two output terminals. Solution: - Check the motor and drive output terminal wiring for a shorted condition. - Replace drive if fault cannot be cleared.
Port 1…5 DPI Loss F81…F85	Cause: - DPI port stopped communicating. - A SCANport device was connected to a drive operating DPI devices at 500k baud. Solution: - If adapter was not intentionally disconnected, check wiring to the port. Replace wiring, port expander, adapters, Main Control Board, or complete drive as required. - Check HIM connection. - If an adapter was intentionally disconnected and the [Logic Mask] bit for that adapter is set to “1”, this fault occurs. To disable this fault, set the [Logic Mask] bit for the adapter to “0.”
F71…F75 Port 1…5 Adapter	Cause: The communications card has a fault. Solution: - Check DPI device event queue and corresponding fault information for the device.
F3 Power Loss	Cause: Excessive DC Bus voltage ripple. Solution: - Monitor the incoming AC line for low voltage or line power interruption. - Check input fuses. - Reduce load.
F104 Pwr Brd Chksum1	Cause: The checksum read from the EEPROM does not match the checksum that is calculated from the EEPROM data. Solution: - Clear the fault or cycle power to the drive.
F105 Pwr Brd Chksum2	Cause: The checksum read from the board does not match the checksum that is calculated. Solution: - Cycle power to the drive. - If problem persists, replace drive.
F112 Power Down Csum	Cause: EEPROM data is corrupt on drive powerup. Solution: - Clear the fault or cycle power to the drive.
F70 Power Unit	Cause: One or more of the output transistors were operating in the active region instead of desaturation. This can be caused by excessive transistor current or insufficient base drive voltage. Solution: - Check for damaged output transistors. - Replace drive.
F107 Replaced MCB-PB	Cause: Main Control Board was replaced and parameters were not programmed. Solution: - Restore defaults. - Reprogram parameters.
F63 Shear Pin	Cause: Programmed [Current Lmt Val] has been exceeded. Enable/Disable with [Fault Config 1]. Solution: Check load requirements and [Current Lmt Val] setting.
F36 SW OverCurrent	Cause: Drive output current has exceeded the 1 ms current rating. - This rating is greater than the 3-second current rating and less than the hardware overcurrent fault level. - It is typically 200…250% of the drive continuous rating. Solution: - Check for excess load, improper DC boost setting. DC brake volts set  too high. - If enabled, check level of flux braking in parameter P549 [Flux Braking %].
F9 Trnsistr OvrTemp	Cause: Output transistors have exceeded their maximum operating temperature. Solution: - Verify that maximum ambient temperature has not been exceeded. - Check fan. - Check for excessive load.
F4 UnderVoltage	Cause: DC bus voltage fell below the min value. Solution: Monitor the incoming AC line for low voltage or line power interruption.
F101 UserSet1 Chksum	Cause: The checksum read from the user set does not match the checksum that is calculated. Solution: - Re-save user set.
F102 UserSet2 Chksum	Cause: The checksum read from the user set does not match the checksum that is calculated. Solution: - Re-save user set.
F103 UserSet3 Chksum	Cause: The checksum read from the user set does not match the checksum that is calculated. Solution: - Re-save user set.

 

How to Read PowerFlex 70 Faults

Diagnosing the PowerFlex 70 requires understanding the Human Interface Module (HIM) and the DPI architecture. Here is how to access diagnostic data:

• The LCD HIM (20-HIM-xx): The keypad displays full text, not just codes.
  • To view history, press the Diagnostics soft key (or navigate to Diagnostics > Faults > View Fault Queue).
  • The drive stores a queue of the last 8 faults with timestamps.
• Understanding DPI Ports: If a fault says “Port X”, it refers to a specific hardware slot:
  • Port 0: The Drive Main Control Board.
  • Port 1: The HIM (Keypad) connected to the front.
  • Port 5: The Communication Adapter (e.g., 20-COMM-E Ethernet card).
• Status Indicators (STS LED):
  • Flashing Yellow: Drive is inhibited (Check “Start Inhibits” parameter).
  • Flashing Red: The drive has a Fault.
  • Solid Red: The hardware has failed permanently.

Frequently Asked Questions (FAQ)

Q: How do I fix “F75 Port 5 Adapter Loss”?

A: This is the most common fault on PowerFlex 70 drives connected to a network. It means the drive cannot communicate with the card in the comm slot (Port 5).

• Check the ribbon cable connecting the 20-COMM card to the drive; these often wiggle loose over years of vibration.
• If the cable is tight, the communication module itself may have failed.

Q: What is “F24 Decel Inhibit”?

A: This occurs when the drive tries to stop the motor, but the load’s inertia is regenerating too much energy back into the drive, raising the DC Bus voltage. The drive pauses deceleration to prevent an “OverVoltage” trip.

• To fix this, increase the Decel Time.
• If fast stopping is required, install a Dynamic Brake Resistor.

Q: How do I reset the drive?

A: You can reset a fault by:

• Pressing the Stop button (if the drive is stopped).
• Pressing the Clear Fault soft key on the HIM.
• Cycling power.
• Toggling a Digital Input configured for “Clear Fault.”