Control TechniquesFault codes
Unidrive M fault codes
Every trip the Control Techniques Unidrive M compact drives can display, listed by the trip number shown in parameter 10.020. Taken from the Unidrive M200/M201 Control User Guide, which covers the trip set used across the M100 to M300 range.
Unidrive M trip table
Listed alphabetically by the string shown on the display, with the trip number it reports in parameter 10.020. Trips marked with a dash carry no trip number. M400 and above add their own encoder, option module and regen trips on top of this set.
| Trip no. | Display | Meaning |
|---|---|---|
| Status | ||
| — | UV | Under voltage — a drive status rather than a trip on the compact M drives: the bus is below the working level, so the drive cannot be enabled. Self-clears when the supply recovers |
| Drive trips | ||
| 2 | OV | DC bus voltage above the peak level, or above the maximum continuous level for 15 seconds — deceleration too fast, braking resistor open, or a regenerative load |
| 3 | OI.AC | Instantaneous output overcurrent — output current above the drive maximum. Cannot be reset for 10 seconds. Check output cabling, motor insulation and the IGBT power stage |
| 4 | OI.br | Braking IGBT overcurrent — short circuit protection in the braking IGBT has operated |
| 5 | PSU | Internal power supply fault on the drive |
| 6 | Et | External trip from a digital input, or a value of 6 written to Pr 10.038 |
| 7 | O.SPd | Motor frequency has exceeded the over-frequency threshold |
| 8 | U.OI | User overcurrent trip — output current above the level set in Pr 04.041 |
| 10 | th.br | Braking resistor over temperature from the hardware thermal monitoring |
| 11 | tun.1 | Required speed could not be reached during autotune |
| 13 | tun.3 | Measured inertia has exceeded the parameter range |
| 18 | tun.S | Autotune test stopped before completion |
| 19 | It.br | Braking resistor I²t overload — check Pr 10.030, 10.031 and 10.061 against the resistor fitted |
| 20 | It.Ac | Output current I²t overload — motor overload, blocked load or incorrect motor rated current |
| 21 | Oht.I | Inverter over temperature from the thermal model — trips at 145 °C, resets at 139 °C |
| 22 | Oht.P | Power stage over temperature — heatsink fan, airflow or a blocked filter |
| 24 | th | Motor thermistor over temperature on terminal 14 — check the threshold in Pr 07.048 and the thermistor continuity |
| 25 | thS | Motor thermistor short circuit or low impedance (below 50 Ω) |
| 26 | O.Ld1 | Digital output overload — total current from the digital outputs and 24V supply is too high |
| 27 | Oh.dc | DC bus over temperature — the drive stops the motor before tripping |
| 28 | cL.A1 | Analogue input 1 current loss in 4-20 mA or 20-4 mA mode — signal below 3 mA or a wiring fault |
| 30 | SCL | Control word watchdog has timed out |
| 31 | EEF | Default parameters have been loaded — the parameter bank or EEPROM checksum has failed |
| 32 | PH.Lo | Supply phase loss or large supply imbalance, detected from DC bus ripple |
| 33 | rS | Measured stator resistance has exceeded the parameter range during autotune |
| 34 | PAd | Keypad has been removed while the drive is taking its reference from the keypad |
| 37 | Pd.S | Power down save error — the parameters saved at power-down could not be verified |
| 90 | LF.Er | Communication lost or excessive errors between the power, control and rectifier modules |
| 92 | OI.Sn | Snubber overcurrent detected |
| 93 | Pb.Er | Communication lost between the control and power processor |
| 97 | d.Ch | Drive parameters are being changed while the drive was commanded to enable — defaults load, mode change or card transfer |
| 98 | Out.P | Output phase loss detected |
| 173 | FAn.F | Fan failure — not fitted, not connected or obstructed. Cannot be reset for 10 seconds |
| NV Media Card trips | ||
| 185 | C.Acc | NV Media Card write fail |
| 178 | C.by | NV Media Card cannot be accessed because an option module is using it |
| 188 | C.cPr | File or data on the card is different to the one in the drive |
| 179 | C.d.E | Card data location already contains data |
| 183 | C.dAt | Card data location does not contain any data |
| 182 | C.Err | Card data structure error |
| 184 | C.FuL | NV Media Card full |
| 175 | C.Pr | Card data blocks are not compatible with the drive derivative |
| 181 | C.rdo | Card has the read-only bit set |
| 174 | C.SL | Option module file transfer to or from the card has failed |
| 187 | C.tyP | Card parameter set is not compatible with the current drive mode |
| Measurement and protection trips | ||
| 189 | OI.A1 | Analogue input 1 current above 24 mA |
| 199 | dESt | Two or more parameters are writing to the same destination parameter |
| 219 | Oht.C | Control stage over temperature — cooling fan control is off; the option module goes to standby |
| 220 | P.dAt | Power system configuration data error |
| 225 | Cur.O | Current feedback offset too large to trim — measurement circuit fault, usually with current flowing at power-up |
| 226 | So.St | Soft-start relay failed to close, or its monitoring circuit has failed |
| 227 | r.All | RAM allocation error |
| 228 | OI.SC | Output phase short circuit detected |
| 231 | Cur.c | Current calibration range error in the current measurement circuit |
| 232 | dr.CF | Drive configuration — the hardware ID does not match the user software ID |
| 234 | Sto | No Safe Torque Off board fitted, or the internal STO board is not fitted correctly |
| 235 | Pb.HF | Power board hardware fault |
| 236 | no.PS | No power board detected |
| 237 | FI.In | Firmware incompatibility — user firmware does not match the power firmware; reflash with Unidrive M Connect |
| 245 | Pb.bt | Power board is in bootloader mode |
| Derivative and option module trips | ||
| 246 | dEr.E | Derivative file missing, invalid or not matched to the control board hardware |
| 247 | Fi.Ch | File changed |
| 248 | dEr.I | Derivative product image error — CRC, memory allocation, task timing or parameter table fault |
| 250 | r.b.ht | Hot rectifier or brake — thermal model has flagged the rectifier or braking IGBT |
| 200 | SL.HF | Option module in slot 1 hardware fault — the sub-trip number gives the cause |
| 201 | SL.tO | Option module in slot 1 started the watchdog function and failed to service it |
| 202 | SL.Er | Option module in slot 1 has detected a fault — see the module user guide for the sub-trip |
| 203 | SL.nF | Option module in slot 1 has been removed since the last power up |
| 204 | SL.dF | Option module in slot 1 is a different type to the one installed when parameters were last saved |
| 218 | tH.Fb | Internal drive thermistor has failed — open or short circuit inside the drive |
| Hardware trips | ||
| — | HF01 – HF23 | Control board hardware trips: CPU address, bus and usage faults, watchdog failure, interrupt crash, stack overflow, non-volatile memory comms, internal flash failure and firmware CRC errors. No trip number, cleared only by cycling power |
Trip strings vary slightly with software version. If your display shows something not listed here, send us a photo of the keypad and we will identify it.
24/7 emergency call-outs
Unidrive M tripping?
Send us the trip code for a free fault assessment, or call 0161 399 0042 for 24/7 emergency call-outs. Fixed-price quote within 24 hours of your unit arriving, with a 12-month warranty.