Understanding trip codes is an important part of keeping your equipment running smoothly.  Below are some of the more common codes you may come across when using your Control Techniques Unidrive M200 series drive:

Trip CodeConditionPossible Cause
C.AccNV Media Card Write failUnable to access the NV Media Card
C.byNV Media Card cannot be
accessed as it is being accessed
by an option module
An attempt has been made to access a file on NV Media Card,
but the NV Media Card is already being accessed by an option
module. No data is transferred.
C.cPr NV Media Card file/data is different
to the one in the drive
A C.cPr trip is initiated if the parameters on the NV Media Card
are different to the drive
C.d.ENV Media Card data location
already contains data
Attempt has been made to store data on a NV Media Card in a
data block which already contains data.
C.dAtNV Media Card data not foundAttempt has been made to access non-existent file or block on
the NV Media Card.
C.ErrNV Media Card data structure
error
Attempt has been made to access the NV Media Card but an
error has been detected in the data structure on the card.
Resetting the trip will cause the drive to erase and create the
correct folder structure.
C.FuLNV Media Card fullThere is not enough space left on the card.
C.OPtNV Media Card trip; option
modules installed are different
between source drive and
destination drive
The parameter data or default difference data is being
transferred from the NV Media Card to the drive, but the option
module category is different between the source and destination
drives.
C.Pr NV Media Card data blocks are not
compatible with the drive derivative
If Drive Derivative is different between the source and target
drives. Refer to the Control User Guide.
C.rdoNV Media Card has the Read Only
bit set
Attempt has been made to modify a read-only NV Media Card or
a read-only data block.
C.rtgNV Media Card trip; Option module
file transfer has failed
The C.SL trip is initiated, if the transfer of an option module file
to or from a module failed because the option module does not
respond correctly.
C.tyPNV Media Card parameter set not
compatible with current drive mode
The drive mode in the data block on the NV Media Card is
different from the current drive mode.
cL.A1Analog input 1 current lossCurrent loss was detected in current mode on Analog input 1
(Terminal 2).
CL.btTrip initiated from the Control WordInitiated by setting bit 12 on the control word when the control
word is enabled. Refer to the Parameter Reference Guide
Cur.cCurrent calibration rangeCurrent calibration range error.
Cur.OCurrent feedback offset errorCurrent offset is too large to be trimmed.
d.ChDrive parameters are being
changed
A user action or a file system write is active that is changing the
drive parameters and the drive has been commanded to enable.
dEr.EDerivative file error Contact the supplier of the drive.
dEr.IDerivative product image errorContact the supplier of the drive.
dEStTwo or more parameters are
writing to the same destination
parameter
The dESt trip indicates that destination output parameters of two
or more logic functions within the drive are writing to the same
parameter.
dr.CFDrive configurationContact the supplier of the drive.
EEFDefault parameters have been
loaded
The EEF trip indicates that default parameters have been
loaded. The exact cause/reason of the trip can be identified from
the sub-trip number (Refer to the Control User Guide).
EtAn External trip is initiatedThe cause of the trip can be identified from the sub trip number
displayed after the trip string.

Sub-trip = 1 Reason - External Trip =1

Refer to the Control User Guide
FAn.FFan failIndicates the fan or fan circuitry has failed
Fi.ChFile changedA file has been changed, power cycle to clear the trip
FI.InFirmware IncompatibilityThe user firmware is incompatible with the power firmware
HFxx tripHardware faultsInternal drive hardware fault (Refer to the Control User Guide).
It.AcOutput current overload timed out
(I2t)
The It.Ac trip indicates a motor thermal overload based on the
output current and motor thermal time constant. The drive will
trip on It.Ac when the accumulator gets to 100 %.
This can occur when:
• There is excessive mechanical load
• Ensure the load is not jammed / sticking
• Check the load on the motor has not changed
• Ensure the motor rated current is not zero
It.brBraking resistor overload timed out
(I2t)
Braking resistor overload has timed out. This can be caused by
excessive braking resistor energy
no.PSNo power boardNo communication between the power and control boards.
O.Ld1Digital output overloadThe total current drawn from the AI-Adaptor 24 V supply or from
the digital output has exceeded the limit.
O.SPdMotor frequency has exceeded the
over frequency threshold
Excessive motor speed (typically caused by mechanical load
driving the motor).
Oh.dcDC bus over temperatureDC bus component over temperature based on a software
thermal model.
Oht.CControl stage over-temperatureControl stage over-temperature detected.
Oht.IInverter over temperature based
on thermal model
IGBT junction over-temperature has been detected based on a
software thermal model.
Oht.PPower stage over temperatureThis trip indicates that a power stage over-temperature has
been detected.
OI.A1Analog input 1 over-currentCurrent input on analog input 1 exceeds 24 mA.
OI.ACInstantaneous output over current
detected
The instantaneous drive output current has exceeded.The set
limit.
Possible solutions:
• Increase acceleration/deceleration rate
• If seen during autotune reduce the voltage boost
• Check for short circuit on the output cabling
• Check integrity of the motor insulation using an insulation
tester
• Is the motor cable length within limits for the frame size
• Reduce the values in the current loop gain parameters
OI.brBraking IGBT over current
detected: short circuit protection
for the braking IGBT activated
Over current has been detected in braking IGBT or braking
IGBT protection has been activated.
Possible cause:
• Check brake resistor wiring
• Check braking resistor value is greater than or equal to the
minimum resistance value
• Check braking resistor insulation
OI.SCOutput phase short-circuitOver-current detected on drive output when enabled.
Out.P Output phase loss detectedPhase loss has been detected at the drive output.
OVDC bus voltage has exceeded the
peak level or maximum continuous
level for 15 seconds
The OV trip indicates that the DC bus voltage has exceeded the
maximum limit.
Possible solutions:
• Increase Deceleration Rate 1 (Pr 04)
• Decrease the braking resistor value (staying above the
minimum value)
• Check nominal AC supply level
• Check for supply disturbances which could cause the DC
bus to rise
• Check motor insulation using a insulation tester
P.dAtPower system configuration data
error
Contact the supplier of the drive.
PAdKeypad has been removedThe PAd trip indicates that the drive is in keypad mode and the
keypad has been disconnected from the drive.
Pb.btPower board is in bootloader modePower board is in bootloader mode
Pb.ErCommunication has been lost /
errors detected between power
control
Communications loss between power and control.
Pb.HFPower board HFPower processor hardware fault - contact the supplier of the
drive
Pd.SPower down save errorError has been detected in the power down save parameters
saved in non-volatile memory.
PH.LoSupply phase lossThe drive has detected an input phase loss or large supply
imbalance.
PSUInternal power supply faultOne or more internal power supply rails are outside limits or
overloaded.
r.All RAM allocation errorOption module derivative image has requested more parameter
RAM than is allowed.
r.b.htHot rectifier/brakeOver-temperature detected on input rectifier or braking IGBT.
rSMeasured resistance has
exceeded the parameter range
The measured stator resistance during an autotune test has
exceeded the maximum possible value of Stator Resistance.
Refer to the Control User Guide.
SCLControl word watchdog has timed
out
The control word has been enabled and has timed out
SL.dFOption module in option slot 1 has
changed
Option slot 1 on the drive is a different type to that installed
when parameters were last saved on the drive.
SL.ErOption module in option slot 1 has
detected a fault
Option module in option slot 1 on the drive has detected an
error
SL.HFOption module 1 hardware faultOption slot 1 on the drive has indicated a hardware fault.
SL.nFOption module in option slot 1 has
been removed
The option module in option slot 1 on the drive has been
removed since the last power up.
SL.tOOption module watchdog function
service error
The option module installed in Slot 1 has started the option
watchdog function and then failed to service the watchdog
correctly.
So.StSoft start relay failed to close, soft
start monitor failed
Soft start relay in the drive failed to close or the soft start
monitoring circuit has failed.
St.HFHardware trip has occurred during
last power down
Hardware trip (HF01 –HF19) has occurred and the drive has
been power cycled. Enter 1299 to Pr 00 or xx.000 to clear trip
StoNo Safe Torque Off board fittedInternal STO board not fitted correctly.
thMotor thermistor over-temperatureThe motor thermistor connected to terminal 14 (digital input 5)
on the control connections has indicated a motor over
temperature.
th.brBrake resistor over temperatureThe th.br trip is initiated if the hardware based braking resistor
thermal monitoring is connected and the resistor overheats.
tH.FbInternal thermistor has failedInternal thermistor has failed.
thSMotor thermistor short circuitThe motor thermistor connected to terminal 14 (digital input 5)
on the control connections, is short circuit or low impedance
(<50 Ω).
tun.SAutotune test stopped before
completion
The drive was prevented from completing an autotune test,
because either the drive enable or the drive run signals were
removed.
tun.1Autotune 1The drive has tripped during a rotating autotune. The cause of
the trip can be identified from the sub-trip number.

Sub-trip-2 Reason=The motor did not reach the required speed during rotating auto-tune or mechanical load measurement.

Refer to the Control User Guide
tun.3Autotune 3RFC-A mode only.
The drive has tripped during a rotating auto-tune or mechanical
load measurement. The cause of the trip can be identified from
the associated sub-trip number

Sub-trip-1 Reason=Measured inertia has exceeded the parameter range during a mechanical
load measurement.

Sub-trip-3 Reason=The mechanical load test has been unable to identify the motor inertia

Refer to the Control User Guide.
U.OIUser OI acThe U.OI trip is initiated if the output current of the drive exceeds
the trip level set by User Over Current Trip Level. Refer to the
Control User Guide.
U.SUser Save error / not completedThe U.S trip indicates that an error has been detected in the user save parameters saved in non-volatile memory.
UP.uSUser Program tripThis trip can be initiated from within an onboard user program. Refer to the Control User Guide.
UPrGUser ProgramAn error has been detected in the onboard user program image.
Refer to the Control User Guide.

In any mode, an alarm is an indication given on the display by alternating the alarm string with the drive status string display. If an action is not taken to eliminate any alarm except "tuning”, the drive may eventually trip. Alarms are not displayed when a parameter is being edited.

Alarm stringDescription
br.resBrake resistor overload. Braking Resistor Thermal Accumulator in the drive has
reached 75.0 % of the value at which the drive will trip.Refer to the Power
Installation Guide.
OV.LdMotor Protection Accumulator in the drive has reached 75.0 % of the value at
which the drive will trip and the load on the drive is >100 %, reduce motor current
(load). Refer to the Parameter Reference Guide
d.OV.LdDrive over temperature. Percentage Of Drive Thermal Trip Level in the drive is
greater than 90 %. Refer to the Parameter Reference Guide
tuningThe autotune procedure has been initialized and an autotune is in progress.
LSLimit switch active. Indicates that a limit switch is active and that is causing the
motor to be stopped
Lo.ACLow voltage mode. See Low AC Alarm in the Control User Guide
I.AC.LtCurrent limit active. See Current Limit Active in the Control User Guide
24.LoStt 24V backup not present. See 24V Alarm Loss Enable in the Control User Guide

If you have an AC / DC drive module breakdown or stability issue our engineers are able to analyse the whole machine to identify where the control issues lie. Our extensive experience in retrofit and new projects means we have the knowledge to look deep into the control system where we commonly find the peripheral devices are faulty rather than the drive module.

Our team of engineers are able to offer on site service and breakdown support throughout the UK to get you up and running again quickly.

Repair

If you have a faulty drive but don't require on site support, Drives and Automation are able to repair them at our repair center in Telford. Our trained engineers will strip down your drive and send you a repair quotation. If you are happy to proceed we will repair the drive, clean it and load test it before returning it to you. Fast turnarounds are usually no problem!

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Replace

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