Unidrive Classic

Troubleshooting a Unidrive with Hardware Fault Trip Codes

unidrive trip codes

Troubleshooting a Unidrive with Hardware Fault Trip Codes

Unidrive Classics are going to trip at one time or another. Refer to this list of Unidrive trip codes next time your Uni1405 or other Unidrive is throwing a mysterious trip error.

HF81 – Software Error (odd address word)
HF82 – Large option module removed
HF83 – Power Board Code Failure
HF84 – Current Offset Trim Failure
HF85 – A to D failure (ES-CC step)
HF86 – Interrupt Watchdog failure
HF87 – Internal ROM check error
HF88 – Watchdog Failure
HF89 – Unused Interrupts (nmi as source)
HF90 – Stack Overflow
HF91 – Stack Underflow
HF92 – Software Error (undefined op code)
HF93 – Software Error (protection fault)
HF94 – Software Error (odd address word)
HF95 – Software Error (odd address inst.)
HF96 – Software Error (illegal ext bus)
HF97 – Level 1 Noise
HF98 – Interrupt Crash
HF99 – Level 1 Crash

A few notes on these Unidrive trip codes:

  • HF trips are internal hardware faults within the drive. Powering the drive down and re-applying power could clear the fault.
  • Resetting the drive will not clear a HF trip.
  • If a HF trip occurs, the Drive Healthy relay will open to indicate this
  • The serial communications will not function during a HF trip
  • The only HF trip that can be caused by the user is a HF82 trip where a
    large option module is removed while the drive is powered up.The drive should be powered down, the module re-fitted correctly and the power reapplied to clear the trip

MRO Electric and Supply has new and refurbished Control Techniques, parts available including the Control Techniques Unidrive Classic and Control Techniques Unidrive SP series. We also offer repair pricing. For more information, please call 800-691-8511 or email sales@mroelectric.com.

Updated on July 1, 2019 by Ryan Dickinson

Joe Kaminski

Joe Kaminski is an industrial automation specialist at MRO Electric. He has a background in industrial engineering and supply chain management. Joe has worked in the automation industry for over 10 years providing support to some of the largest companies in the world. For more info, visit www.mroelectric.com.

10 thoughts to “Troubleshooting a Unidrive with Hardware Fault Trip Codes”

  1. VFD shows fault codes “HFHFtr” trip. How can the fault be cleared and put it in operation

  2. HF trips are internal hardware faults within the drive. Powering the drive down and re-applying power could clear the fault.

  3. HF84 is the fault showing in my unidrive. I have tryed powering off/on a number of times but with no luck. Any other solutions?

  4. At Uni1405 how can i unlock the parameters?I tried everything the manual says but

    when i go for example at 0.40 parameter and press i have -inh- at
    the lower display of the drive.
    Is there another way ?


  5. Hi Good Afternoon,

    We Are Facing Alarm – trip 01.AC, ( Servo Drive Model No : SP 1405 Sr no: 431163026] Ferquently The Drive Connected To Spindle Motor,
    And Power Transmission Trough Timming Belt ,

    As Per maual Instruction We Check All The Possible Cause But Still Problem Not Sloved Kindly Provide Assistance To Over This Issue,

    We Are Looking For Our Valuable Reply on This Issue

    Thank You!!!

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