Troubleshooting / Festo CMMT errors

Festo CMMT Error Codes

The diagnostic messages of Festo CMMT-AS and CMMT-ST servo drives: what each one means, how the drive reacts, the likely causes, the first checks with the parameters to look at, and how to log it so it stops coming back.

How messages show

The CMMT shows its state on four front LEDs instead of a 7-segment display: the Status LED flashes red for an error, flashes yellow for a warning, flashes green when ready with the power stage off and is steady green when the controller is enabled. Fast red flashing means an unexpected exception (restart, then call Festo service).

The Power and Safety LEDs show supply and STO state. Read the message text in Festo Automation Suite (Diagnosis, Device State for current messages, Error Log for the non-volatile error memory), on the optional CDSB operator unit, in the drive web server, or over the fieldbus.

Each message ID starts with D0 (system) or D1 (axis 1), followed by main group, subgroup and error number, for example 07 | 02 | 00126. The same message also shows as a 1-part decimal number (117571710), and 16-bit fieldbus channels such as the PROFINET fault buffer PNU 947 carry only the error number (126).

Parameters are written Px.nnn, where x is 0 for system and 1 for axis 1 (for example P1.463).

To acknowledge, first remove the cause so the message changes from active to cancelled, then use a rising edge on the ERR-RST input, the fieldbus (CiA 402 control word bit 7 or PROFIdrive STW1.7 from 0 to 1), Acknowledge All in Automation Suite, the web server, or Acknowledge all on the CDSB. Serious errors cannot be acknowledged and need a power off and on.

Safety first.
The CMMT-AS stores dangerous voltage in its DC link capacitors for up to 5 minutes after power off: switch off at the main switch, lock it out, and wait at least 5 minutes before touching the power connections. Never pull power plugs while live.

STO only blocks the power stage: it does not disconnect the drive from the supply in the sense of electrical safety and does not protect against electric shock, only against dangerous movement. With external loads on the axis (for example a vertical axis), STO alone does not hold the axis, so use a mechanical brake as well.

Sources: Festo operating instructions 8215508 (CMMT-AS-C2/3/5-11A-P3-...-S1) and 8214099 (CMMT-ST-C8-1C-...-S0), and manual 8183882 (CMMT-AS-C2/4-3A-...). Follow lockout/tagout and your site's safe-work procedures, and check the manual for your exact model before you act.

Quick lookup

Errors stop the axis and the machine, so in OEE they are availability losses; warnings let it keep running until you act.

Type a number or a word (following error, DC link, encoder, STO) to filter the list. Click a message for its causes and first checks.

71 codes

CodeModelName
07 | 02 | 00126CMMT-AS, CMMT-STPosition: following error
07 | 02 | 00127CMMT-AS, CMMT-STVelocity: following error
07 | 02 | 00658CMMT-AS, CMMT-STAcceleration following error
01 | 02 | 00013CMMT-AS, CMMT-STI²t monitoring: motor error limit
01 | 02 | 00012CMMT-AS, CMMT-STI²t monitoring: motor warning limit
01 | 02 | 00015CMMT-AS, CMMT-STI²t monitoring: output stage error limit
01 | 02 | 00014CMMT-AS, CMMT-STI²t monitoring: output stage warning limit
01 | 02 | 00017CMMT-AS, CMMT-STI²t monitoring: output stage v0 error limit
01 | 02 | 00259CMMT-STI²t monitoring: motor model error limit
01 | 02 | 00258CMMT-STI²t monitoring: motor model warning limit
01 | 01 | 00011CMMT-AS, CMMT-STOver-current monitoring
01 | 01 | 00010CMMT-AS, CMMT-STShort circuit motor phases/braking resistor
02 | 02 | 00030CMMT-AS, CMMT-STOvervoltage in DC link
02 | 02 | 00031CMMT-AS, CMMT-STUndervoltage in DC link
02 | 02 | 00032CMMT-AS, CMMT-STDC link warning threshold reached
01 | 03 | 00020CMMT-AS, CMMT-STError: pulse energy monitoring, braking resistor
01 | 03 | 00019CMMT-AS, CMMT-STWarning: pulse energy monitoring, braking resistor
02 | 03 | 00038CMMT-AS, CMMT-STUndervoltage in load voltage
02 | 03 | 00039CMMT-AS, CMMT-STOvervoltage in load voltage
02 | 03 | 00036CMMT-ASNo load voltage
02 | 03 | 00037CMMT-ASLoad voltage interruption detected
02 | 03 | 00040CMMT-ASPhase failure in load voltage
02 | 02 | 00033CMMT-ASDC link voltage too low following power failure
02 | 02 | 00034CMMT-ASDC link precharge time exceeded
02 | 03 | 00251CMMT-STLimit value of energy recovery exceeded
02 | 01 | 00022CMMT-AS, CMMT-STUndervoltage in logic supply 24V
02 | 01 | 00023CMMT-AS, CMMT-STOvervoltage in logic supply 24V
09 | 01 | 00148CMMT-AS, CMMT-STSTO: Discrepancy time exceeded
09 | 01 | 00150CMMT-AS, CMMT-STSequence monitoring #STO-A/B
09 | 00 | 00146CMMT-AS, CMMT-STSafety function requested
05 | 02 | 00062CMMT-AS, CMMT-STTask ignored as safety function requested
05 | 02 | 00061CMMT-AS, CMMT-STTask ignored controller enable failed
03 | 02 | 00051CMMT-AS, CMMT-STPower unit overtemperature
03 | 02 | 00050CMMT-AS, CMMT-STWarning threshold: Power unit overtemperature
03 | 01 | 00047CMMT-AS, CMMT-STDevice overtemperature
03 | 01 | 00046CMMT-AS, CMMT-STWarning threshold: Device overtemperature
03 | 03 | 00055CMMT-AS, CMMT-STMotor overtemperature
03 | 03 | 00054CMMT-AS, CMMT-STWarning threshold: Motor overtemperature
10 | 01 | 00155CMMT-ASError: fan faulty
07 | 01 | 00114CMMT-AS, CMMT-STNegative hardware limit switch reached
07 | 01 | 00115CMMT-AS, CMMT-STPositive hardware limit switch reached
07 | 01 | 00118CMMT-AS, CMMT-STError: both hardware limit switches activated
07 | 01 | 00109CMMT-AS, CMMT-STNegative software limit position
07 | 01 | 00110CMMT-AS, CMMT-STPositive software limit position
05 | 01 | 00057CMMT-AS, CMMT-STHoming: Timeout
05 | 01 | 00058CMMT-AS, CMMT-STHoming: Search path exceeded
05 | 01 | 00056CMMT-AS, CMMT-STConfiguration of homing run invalid
05 | 02 | 00067CMMT-AS, CMMT-STTask ignored as referencing missing
08 | 04 | 00143CMMT-AS, CMMT-STEtherCAT process data communication failed
08 | 03 | 00391CMMT-AS, CMMT-STProcess data communication failed
08 | 13 | 00394CMMT-AS, CMMT-STInvalid process data
08 | 00 | 00140CMMT-AS, CMMT-STFailure of fieldbus synchronisation signal
08 | 04 | 00281CMMT-AS, CMMT-STProcess data not received at Sync time
08 | 09 | 00299CMMT-AS, CMMT-STError Sign of Life
08 | 09 | 00294CMMT-AS, CMMT-STPLC Control is not set
07 | 04 | 00136CMMT-AS, CMMT-STCommutation finding failed
07 | 04 | 00137CMMT-AS, CMMT-STCommutation finding direction error
18 | 00 | 00092CMMT-AS, CMMT-STMotor change detected, commutation angle invalid
18 | 03 | 00235CMMT-AS, CMMT-STIncremental encoder analysis invalid
18 | 01 | 00229CMMT-ASCommon error EnDat 2.2
02 | 04 | 00042CMMT-ASEncoder supply voltage monitoring thresholds
05 | 02 | 00066CMMT-AS, CMMT-STTask ignored as encoder not ready
07 | 02 | 00128CMMT-AS, CMMT-STVelocity too high
07 | 02 | 00129CMMT-AS, CMMT-STOut of target range
07 | 03 | 00135CMMT-AS, CMMT-STLimit for velocity or current active
07 | 03 | 00134CMMT-AS, CMMT-STVoltage limitation active
05 | 02 | 00078CMMT-AS, CMMT-STStop ramp: Timeout
05 | 02 | 00064CMMT-AS, CMMT-STTask ignored as DC link coupling not ready
05 | 02 | 00283CMMT-AS, CMMT-STBrake test failed
10 | 01 | 00156CMMT-AS, CMMT-STCommon error power output stage
13 | 02 | 00217CMMT-AS, CMMT-STAuto tuning aborted

Each code: causes and first checks

07 | 02 | 00126: Position: following error

Hits OEE: Availability

What it means: The actual position fell behind (or ran ahead of) the setpoint by more than the position following error window for longer than the damping time, while the axis was still moving to its target. In the 1-part format it shows as 117571710; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 126.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.4622 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Speed, acceleration or jerk set too high for the axis and load
  • Mechanics jammed, stiff, or the load is heavier than planned
  • Holding brake not opening or dragging
  • Controller gains too soft, or the drive is sitting at its current or torque limit
  • Following error window (Px.463) or damping time (Px.462) set too tight

First checks, in this order

  1. Record the move with the trace in Festo Automation Suite: plot setpoint position, actual position and Px.4682 (actual position following error).
  2. Lower the speed and acceleration of the motion task and test again.
  3. With power off and vertical axes secured, move the axis by hand to check for binding, a jammed guide or a brake that does not release.
  4. Check the monitoring window Px.463 and the damping time Px.462 against what the machine really needs.
  5. If the drive hits its current limit during the move (message 07 | 03 | 00135), check motor sizing and the limits Px.854 to Px.856.

07 | 02 | 00127: Velocity: following error

Hits OEE: Availability

What it means: The actual speed differed from the setpoint speed by more than the velocity following error window for longer than the velocity damping time. In the 1-part format it shows as 117571711; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 127.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.4624 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Acceleration or deceleration set too high, so the motor cannot follow the speed profile
  • Load inertia or friction higher than the tuning expects
  • Mechanics jammed or brake dragging
  • Drive at its current, torque or voltage limit
  • Velocity window (Px.464) or damping time (Px.4690) set too tight

First checks, in this order

  1. Trace setpoint speed, actual speed and Px.4683 (actual velocity following error) during the move.
  2. Reduce acceleration and deceleration of the motion task and test again.
  3. Check the mechanics and the holding brake for drag or blocking.
  4. Check the monitoring window Px.464 and damping time Px.4690.
  5. Look for limit messages such as 07 | 03 | 00135 or 07 | 03 | 00134 in the message list at the same time stamp.

07 | 02 | 00658: Acceleration following error

Hits OEE: Availability

What it means: The difference between setpoint and actual acceleration stayed outside its monitoring window (Px.101735) for longer than the settling time (Px.101731). In the 1-part format it shows as 117572242; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 658.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Can be changed with Px.101753 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Dynamic values too high for the motor and load
  • Motor phases connected in the wrong order
  • Encoder counting direction does not match the motor direction
  • Monitoring window Px.101735 too tight

First checks, in this order

  1. Trace the move and compare setpoint and actual acceleration.
  2. Reduce the dynamic values of the motion task.
  3. Check the motor phase sequence (U, V, W) at the drive and the motor plug.
  4. Check the encoder direction of rotation in the drive configuration.
  5. Check the window Px.101735 and settling time Px.101731.

01 | 02 | 00013: I²t monitoring: motor error limit

Hits OEE: Availability

What it means: The calculated thermal load of the motor (current squared over time) reached the error limit, so the drive stops the axis to protect the motor. In the 1-part format it shows as 16908301; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 13.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.6321 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Mechanics blocked or stiff, so the motor draws high current all the time
  • Motor too small for the duty cycle
  • Drive package undersized for the application
  • Holding brake not releasing

First checks, in this order

  1. Check the axis for jamming, stiff guides or a dragging brake.
  2. Review the duty cycle: long holds with load, too little pause time, or high acceleration on every cycle.
  3. Check motor and drive sizing for the real load.
  4. Check the motor nominal current Px.7117 and maximum current Px.7120 in the drive configuration.
  5. Let the motor cool down, then acknowledge and test with lower dynamics.

01 | 02 | 00012: I²t monitoring: motor warning limit

Warning: act before it becomes a stop

What it means: The calculated thermal load of the motor reached the warning limit. The axis keeps running, but the error limit (01 | 02 | 00013) is next. In the 1-part format it shows as 16908300; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 12.[1][2]

Machine response: Default: warning (motion continues, status LED flashes yellow). Can be changed with Px.6319 (warning, information or ignore).

Likely causes

  • Movement orders too dynamic for the motor
  • Holding brake dragging
  • Mechanics blocked or stiff

First checks, in this order

  1. Reduce speed and acceleration of the motion tasks or add pause time.
  2. Check that the holding brake opens fully.
  3. Check the mechanics for stiffness or blocking.

01 | 02 | 00015: I²t monitoring: output stage error limit

Hits OEE: Availability

What it means: The calculated thermal load of the drive's power output stage reached the error limit, so the drive stops the axis to protect itself. In the 1-part format it shows as 16908303; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 15.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.6325 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Mechanics blocked or stiff
  • Servo drive too small for the current the application needs
  • Holding brake not releasing

First checks, in this order

  1. Check the axis for jamming and the brake for drag.
  2. Compare the RMS current of the cycle with the drive rating; check the drive package sizing.
  3. Reduce dynamics or add pause time in the cycle, then acknowledge and test.

01 | 02 | 00014: I²t monitoring: output stage warning limit

Warning: act before it becomes a stop

What it means: The thermal load of the drive's power output stage reached the warning limit. Motion continues for now. In the 1-part format it shows as 16908302; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 14.[1][2]

Machine response: Default: warning (motion continues, status LED flashes yellow). Can be changed with Px.6323 (warning, information or ignore).

Likely causes

  • Mechanics blocked or stiff
  • Servo drive undersized for the cycle
  • Holding brake dragging

First checks, in this order

  1. Check the mechanics and the brake.
  2. Review drive sizing and the duty cycle before the error limit (01 | 02 | 00015) trips.

01 | 02 | 00017: I²t monitoring: output stage v0 error limit

Hits OEE: Availability

What it means: The output stage overheated while the motor was standing still with current flowing (for example holding a load against gravity or pushing against a stop). In the 1-part format it shows as 16908305; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 17.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.6329 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Holding a load at standstill with high current for a long time
  • Long dwell times under torque, such as press-fit or clamping against a fixed stop
  • Motor turning slower than about 5 Hz electrical frequency while carrying high current

First checks, in this order

  1. Reduce the set current or set torque during the hold.
  2. Shorten the standstill time under load, or let the holding brake carry the load.
  3. Where possible, allow movement above 5 Hz electrical rotational frequency instead of long holds.

01 | 02 | 00259: I²t monitoring: motor model error limit

Hits OEE: Availability

What it means: On the CMMT-ST, the motor thermal model (I²t) reached its error limit, so the stepper or EC motor is stopped to protect it from overheating. In the 1-part format it shows as 16908547; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 259.[2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.63021 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Movement orders too dynamic for the motor
  • Holding brake dragging
  • Mechanics blocked or stiff

First checks, in this order

  1. Reduce speed, acceleration or holding current in the motion tasks.
  2. Check that the holding brake opens.
  3. Check the mechanics for stiffness, then acknowledge after the motor cools.

01 | 02 | 00258: I²t monitoring: motor model warning limit

Warning: act before it becomes a stop

What it means: On the CMMT-ST, the motor thermal model reached its warning limit. The axis keeps running for now. In the 1-part format it shows as 16908546; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 258.[2]

Machine response: Default: warning (motion continues, status LED flashes yellow). Can be changed with Px.63019 (warning, information or ignore).

Likely causes

  • Movement orders too dynamic for the motor
  • Holding brake dragging
  • Mechanics blocked or stiff

First checks, in this order

  1. Reduce dynamics or add pause time.
  2. Check brake and mechanics before the error limit 01 | 02 | 00259 trips.

01 | 01 | 00011: Over-current monitoring

Hits OEE: Availability

What it means: The over-current monitor tripped: current in the power stage went above the safe limit. In the 1-part format it shows as 16842763; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 11.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • Short circuit or earth fault in the motor cable or motor
  • Short circuit in the braking resistor wiring
  • Wrong commutation angle (motor changed, encoder offset lost)

First checks, in this order

  1. With power off and after the discharge time, check the motor cable and motor phases for short circuits and earth faults.
  2. Check the braking resistor wiring for a short circuit.
  3. Check the commutation angle; run commutation angle finding again if the motor or encoder was changed.

01 | 01 | 00010: Short circuit motor phases/braking resistor

Hits OEE: Availability

What it means: The drive detected a short circuit on the motor phases or on the braking resistor output and switched the power stage off. In the 1-part format it shows as 16842762; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 10.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • Damaged motor cable (crushed, chafed in a drag chain)
  • Motor winding fault
  • Braking resistor or its wiring shorted

First checks, in this order

  1. Disconnect power and wait for the DC link to discharge.
  2. Unplug the motor cable and measure phase to phase and phase to earth on cable and motor.
  3. Check the braking resistor and its wiring.
  4. Fix the short before powering up again.

02 | 02 | 00030: Overvoltage in DC link

Hits OEE: Availability

What it means: The DC link voltage rose above the switch-off limit, usually because the motor fed braking energy back into the drive. In the 1-part format it shows as 33685534; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 30.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • Deceleration too fast for the braking capacity
  • Braking resistor missing, wrong value (resistance too high) or disconnected
  • Supply voltage too high

First checks, in this order

  1. Check that a braking resistor is fitted and wired, and that its value matches the dimensioning.
  2. Increase deceleration time or lower the deceleration of the motion tasks.
  3. Check the DC link switch-off limit P0.4812.
  4. Measure the supply voltage.

02 | 02 | 00031: Undervoltage in DC link

Hits OEE: Availability

What it means: The DC link voltage fell below the undervoltage threshold while the drive needed it. In the 1-part format it shows as 33685535; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 31.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.487 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Supply voltage missing, low or sagging under load
  • Main contactor or fuse opened
  • Undervoltage threshold P0.4814 set too high

First checks, in this order

  1. Check the power supply, fuses and contactors.
  2. Measure the DC link voltage.
  3. Couple DC links of several drives only where Festo allows it.
  4. Check the undervoltage threshold P0.4814.

02 | 02 | 00032: DC link warning threshold reached

Warning: act before it becomes a stop

What it means: The DC link voltage reached its warning threshold. Festo marks this message as information only. In the 1-part format it shows as 33685536; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 32.[1][2]

Machine response: Default: warning (motion continues, status LED flashes yellow). Can be changed with Px.489 (warning, information or ignore).

Likely causes

  • DC link voltage close to its limit, for example during braking or with a weak supply

First checks, in this order

  1. No action needed for the message itself; watch for 02 | 02 | 00030 or 02 | 02 | 00031 following it.
  2. If it appears often, review braking energy and supply voltage.

01 | 03 | 00020: Error: pulse energy monitoring, braking resistor

Hits OEE: Availability

What it means: The braking resistor absorbed more pulse energy than allowed, so the drive stops to protect it. In the 1-part format it shows as 16973844; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 20.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.6515 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Deceleration too hard or too frequent
  • Braking resistor too small for the energy of the application
  • Braking resistor parameters wrong

First checks, in this order

  1. Reduce deceleration or the number of hard stops.
  2. Use a braking resistor with a higher pulse energy rating.
  3. Check the external braking resistor parameters P0.6510, P0.6511 and P0.6512.

01 | 03 | 00019: Warning: pulse energy monitoring, braking resistor

Warning: act before it becomes a stop

What it means: The braking resistor is close to its pulse energy limit. Motion continues for now. In the 1-part format it shows as 16973843; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 19.[1][2]

Machine response: Default: warning (motion continues, status LED flashes yellow). Can be changed with Px.6513 (warning, information or ignore).

Likely causes

  • Hard or frequent decelerations
  • Braking resistor rating too small

First checks, in this order

  1. Reduce deceleration dynamics.
  2. Consider a braking resistor with higher pulse energy before 01 | 03 | 00020 trips.

02 | 03 | 00038: Undervoltage in load voltage

Hits OEE: Availability

What it means: The load (power) supply voltage dropped below its limit. In the 1-part format it shows as 33751078; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 38.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.519 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Weak or overloaded power supply
  • Loose terminal or long, thin supply cable
  • Power failure detection set wrong (P0.493)

First checks, in this order

  1. Measure the load supply at the drive terminals while the axis moves.
  2. Check terminals, fuses and supply cables.
  3. Check the power failure detection setting P0.493.

02 | 03 | 00039: Overvoltage in load voltage

Hits OEE: Availability

What it means: The load (power) supply voltage went above its limit. In the 1-part format it shows as 33751079; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 39.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.517 (stop category 1 or warning).

Likely causes

  • Supply voltage too high or unstable
  • Power failure detection set wrong (P0.494)

First checks, in this order

  1. Measure the supply voltage at the drive.
  2. Check the power failure detection setting P0.494.

02 | 03 | 00036: No load voltage

Hits OEE: Availability

What it means: The CMMT-AS sees no mains (load) voltage, for example when it is asked to run with only the 24 V logic supply present. In the 1-part format it shows as 33751076; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 36.[1]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.501 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Mains supply switched off, contactor open or fuse blown
  • Emergency stop circuit cut the mains feed
  • Wiring fault at the mains connector

First checks, in this order

  1. Check the mains supply, contactor and fuses.
  2. Check the mains connector on the drive.
  3. Look at the Power LED: steady yellow means logic supply present but AC supply missing.

02 | 03 | 00037: Load voltage interruption detected

Warning: act before it becomes a stop

What it means: The CMMT-AS detected a short interruption of the mains voltage. In the 1-part format it shows as 33751077; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 37.[1]

Machine response: Default: warning (motion continues, status LED flashes yellow). Can be changed with Px.503 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Mains dips or short dropouts
  • Distortion of the mains voltage when a line choke is used

First checks, in this order

  1. Check the mains supply quality.
  2. With a line choke, the mains monitoring sensitivity can be reduced with Px.281520 (a higher value means less sensitive).

02 | 03 | 00040: Phase failure in load voltage

Warning: act before it becomes a stop

What it means: The CMMT-AS detected that one mains phase is missing. In the 1-part format it shows as 33751080; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 40.[1]

Machine response: Default: warning (motion continues, status LED flashes yellow). Can be changed with Px.5111 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Blown fuse on one phase
  • Loose terminal or broken wire on one phase
  • Supply phase lost upstream

First checks, in this order

  1. Measure all three phases at the drive input.
  2. Check fuses and terminals on each phase.

02 | 02 | 00033: DC link voltage too low following power failure

Hits OEE: Availability

What it means: After a mains interruption, the CMMT-AS DC link voltage had dropped too low. In the 1-part format it shows as 33685537; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 33.[1]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • Mains dropouts or brownouts
  • Loose contact in the supply wiring

First checks, in this order

  1. Check the power supply for dropouts.
  2. Check supply wiring and terminals for loose contacts.

02 | 02 | 00034: DC link precharge time exceeded

Hits OEE: Availability

What it means: The CMMT-AS DC link did not charge up within the allowed time after power on. In the 1-part format it shows as 33685538; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 34.[1]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • Problem in DC link coupling between drives
  • Braking resistor value wrong or its wiring interrupted
  • Lower DC link voltage limit P0.4814 set wrong
  • Drive defective

First checks, in this order

  1. Check the DC link coupling, if used.
  2. Check the connected braking resistor value and wiring.
  3. Check P0.4814 (lower limit of the DC link voltage).
  4. If all checks pass, the drive may be defective.

02 | 03 | 00251: Limit value of energy recovery exceeded

Hits OEE: Availability

What it means: On the CMMT-ST, the energy fed back from the motor pushed the supply above the energy recovery limit. In the 1-part format it shows as 33751291; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 251.[2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • Hard braking feeding energy into a supply that cannot absorb it
  • Switch-off threshold P0.10185 set wrong

First checks, in this order

  1. Check the power supply (can it absorb regenerated energy?).
  2. Check the switch-off threshold P0.10185.
  3. Reduce deceleration dynamics.

02 | 01 | 00022: Undervoltage in logic supply 24V

Hits OEE: Availability

What it means: The 24 V logic supply of the drive dropped too low. In the 1-part format it shows as 33619990; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 22.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • 24 V power supply overloaded or failing
  • Loose 24 V terminal or long supply cable

First checks, in this order

  1. Measure the 24 V at the drive terminals.
  2. Check the 24 V power supply and wiring.
  3. Restart the device after fixing the supply.

02 | 01 | 00023: Overvoltage in logic supply 24V

Hits OEE: Availability

What it means: The 24 V logic supply of the drive is too high. In the 1-part format it shows as 33619991; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 23.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • 24 V power supply set too high or defective

First checks, in this order

  1. Measure the logic supply at the drive and correct the power supply.

09 | 01 | 00148: STO: Discrepancy time exceeded

Hits OEE: Availability

What it means: The two STO inputs (#STO-A and #STO-B) did not switch together within the allowed discrepancy time. In the 1-part format it shows as 151060628; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 148.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • One STO channel wired loose or broken
  • Safety relay or door switch switching the channels at different times
  • Discrepancy time Px.391 too short

First checks, in this order

  1. Check the timing of the #STO-A and #STO-B signals (both must switch together).
  2. Check the STO wiring and the safety relay outputs.
  3. Check the discrepancy time setting Px.391.

09 | 01 | 00150: Sequence monitoring #STO-A/B

Hits OEE: Availability

What it means: The order or timing in which the #STO-A and #STO-B inputs switched was not valid. In the 1-part format it shows as 151060630; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 150.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • Safety device switching the two channels in a wrong sequence
  • Contact bounce or a loose STO connection

First checks, in this order

  1. Check the timing and sequence of both STO input signals.
  2. Check STO wiring and terminals.

09 | 00 | 00146: Safety function requested

Warning: act before it becomes a stop

What it means: A safety sub-function (for example STO) was requested, normally because an emergency stop or guard opened. Information only. In the 1-part format it shows as 150995090; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 146.[1][2]

Machine response: Default: information (logged in the message list only). Can be changed with Px.821 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Emergency stop pressed or guard door open
  • Safety relay output off

First checks, in this order

  1. Check the emergency stop and guards, then reset the safety circuit.
  2. Watch the Safety LED: steady yellow means the safety function is requested and active.

05 | 02 | 00062: Task ignored as safety function requested

Warning: act before it becomes a stop

What it means: A motion command was refused because a safety sub-function (such as STO) is requested. In the 1-part format it shows as 84017214; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 62.[1][2]

Machine response: Default: warning (motion continues, status LED flashes yellow). Fixed, cannot be changed.

Likely causes

  • STO inputs low (emergency stop or guard open)
  • Safety circuit not reset

First checks, in this order

  1. Check that the safety function inputs have the correct logic level (both STO inputs at 24 V when no safety function is wanted).
  2. Reset the safety circuit, then repeat the command.

05 | 02 | 00061: Task ignored controller enable failed

Hits OEE: Availability

What it means: A motion command was refused because the controller enable is missing. In the 1-part format it shows as 84017213; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 61.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • CTRL-EN input not set
  • Controller enable missing over the fieldbus
  • PLC sequence sends the move before enabling

First checks, in this order

  1. Set the CTRL-EN enable input.
  2. Check that the PLC sets the enable over the fieldbus before sending the move.

03 | 02 | 00051: Power unit overtemperature

Hits OEE: Availability

What it means: The power unit (output stage) temperature passed its error limit. In the 1-part format it shows as 50462771; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 51.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • Drive fan defective or blocked
  • Drive overloaded in continuous operation
  • Hot control cabinet or dirty cabinet fan filter
  • Not enough space around the drive

First checks, in this order

  1. Check the drive fan and cabinet cooling; clean the fan filter.
  2. Check the installation clearances.
  3. Review drive sizing for continuous load.
  4. Check the warning threshold P0.9315.

03 | 02 | 00050: Warning threshold: Power unit overtemperature

Warning: act before it becomes a stop

What it means: The power unit temperature reached its warning threshold. In the 1-part format it shows as 50462770; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 50.[1][2]

Machine response: Default: warning (motion continues, status LED flashes yellow). Can be changed with Px.926 (warning, information or ignore).

Likely causes

  • Fan defective, dirty filter, hot cabinet
  • Continuous overload

First checks, in this order

  1. Check cooling and the cabinet fan filter.
  2. Check the warning threshold P0.9314.
  3. Reduce load before 03 | 02 | 00051 trips.

03 | 01 | 00047: Device overtemperature

Hits OEE: Availability

What it means: The drive's internal device temperature passed its error limit. In the 1-part format it shows as 50397231; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 47.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • Drive fan defective
  • Drive overloaded
  • Poor cabinet cooling or dirty filter

First checks, in this order

  1. Check the drive fan and cabinet cooling.
  2. Check the installation conditions.
  3. Review drive sizing for continuous operation.
  4. Check the threshold P0.9311.

03 | 01 | 00046: Warning threshold: Device overtemperature

Warning: act before it becomes a stop

What it means: The drive's internal temperature reached its warning threshold. In the 1-part format it shows as 50397230; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 46.[1][2]

Machine response: Default: warning (motion continues, status LED flashes yellow).

Likely causes

  • Fan, filter or cabinet cooling problem
  • Continuous overload

First checks, in this order

  1. Check cooling and the threshold P0.9310.

03 | 03 | 00055: Motor overtemperature

Hits OEE: Availability

What it means: The motor temperature (from its sensor) passed the error limit. In the 1-part format it shows as 50528311; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 55.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.9419 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Motor overloaded
  • Temperature sensor defective or set up wrong
  • Broken sensor wire
  • Current limits set too high

First checks, in this order

  1. Let the motor cool and check the load and duty cycle.
  2. Check the sensor cable for a break.
  3. Check the sensor settings and its characteristic curve.
  4. Check the current controller settings and current limits.

03 | 03 | 00054: Warning threshold: Motor overtemperature

Warning: act before it becomes a stop

What it means: The motor temperature reached its warning threshold. In the 1-part format it shows as 50528310; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 54.[1][2]

Machine response: Default: warning (motion continues, status LED flashes yellow). Can be changed with Px.9417 (warning, information or ignore).

Likely causes

  • Motor overloaded
  • Sensor problem or wrong sensor setting

First checks, in this order

  1. Check the load, cooling and sensor before 03 | 03 | 00055 trips.

10 | 01 | 00155: Error: fan faulty

Hits OEE: Availability

What it means: The CMMT-AS internal fan reports a fault. In the 1-part format it shows as 167837851; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 155.[1]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • Fan blocked by dirt or a foreign object
  • Fan connection loose
  • Fan worn out

First checks, in this order

  1. Check that the fan turns freely and is not blocked.
  2. Check the fan connection.
  3. Contact Festo service if the fan is defective.

07 | 01 | 00114: Negative hardware limit switch reached

Hits OEE: Availability

What it means: The axis reached the negative hardware limit switch. In the 1-part format it shows as 117506162; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 114.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.101102 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Motion order drives past the allowed travel
  • Homing or position values wrong
  • Limit switch set too far in, or faulty

First checks, in this order

  1. Check the motion order and target positions.
  2. Check the limit switch position and signal.
  3. Jog the axis back off the switch after acknowledging.

07 | 01 | 00115: Positive hardware limit switch reached

Hits OEE: Availability

What it means: The axis reached the positive hardware limit switch. In the 1-part format it shows as 117506163; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 115.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.101106 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Motion order drives past the allowed travel
  • Homing or position values wrong
  • Limit switch set too far in, or faulty

First checks, in this order

  1. Check the motion order and target positions.
  2. Check the limit switch position and signal.
  3. Jog the axis back off the switch after acknowledging.

07 | 01 | 00118: Error: both hardware limit switches activated

Hits OEE: Availability

What it means: Both hardware limit switch inputs are active at the same time, which is not physically possible on a working axis. In the 1-part format it shows as 117506166; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 118.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.101110 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Broken wire on normally closed limit switches
  • Wrong switch type (NO or NC) set in the parameters
  • 24 V missing on the limit switch supply

First checks, in this order

  1. Check the limit switch wiring and 24 V supply.
  2. Check the parameter setting for the switch type.
  3. Restart the device after fixing.

07 | 01 | 00109: Negative software limit position

Hits OEE: Availability

What it means: The axis reached the negative software end position. In the 1-part format it shows as 117506157; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 109.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.4632 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Motion trajectory runs close to or past the end stop
  • Software end positions (Px.4629, Px.4630) set wrong
  • Stop ramp (Px.12101, Px.12111) gentler than the move, so the axis overshoots

First checks, in this order

  1. Check the motion trajectory and target positions.
  2. Check the software end positions Px.4629 and Px.4630.
  3. Check whether automatic braking is active (Px.4631).
  4. If the stop ramp is lower than the trajectory values, increase the stop ramp (Px.12101, Px.12111).

07 | 01 | 00110: Positive software limit position

Hits OEE: Availability

What it means: The axis reached the positive software end position. In the 1-part format it shows as 117506158; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 110.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.4634 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Motion trajectory runs close to or past the end position
  • Software end position Px.4630 set wrong
  • Stop ramp gentler than the move

First checks, in this order

  1. Check the motion trajectory and target positions.
  2. Check the software end position Px.4630 and automatic braking Px.4631.
  3. Increase the stop ramp (Px.12101, Px.12111) if it is lower than the trajectory values.

05 | 01 | 00057: Homing: Timeout

Hits OEE: Availability

What it means: The homing run did not finish within the homing timeout. In the 1-part format it shows as 83951673; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 57.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.8452 (stop category 0, 1 or 2).

Likely causes

  • Homing speed too slow for the travel
  • Axis stalls at the end stop without the standstill being detected
  • Timeout Px.842 too short

First checks, in this order

  1. Check the homing timeout Px.842.
  2. Homing to an end stop: check the standstill window Px.8415 and limit monitoring Px.8414.
  3. Homing to a stop: check standstill window Px.4627 and limit monitoring Px.4626.
  4. Increase the homing speed and acceleration.

05 | 01 | 00058: Homing: Search path exceeded

Hits OEE: Availability

What it means: The axis travelled the full search path during homing without finding the switch or end stop. In the 1-part format it shows as 83951674; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 58.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.8454 (stop category 0, 1 or 2).

Likely causes

  • Reference or limit switch not working or not reached
  • Slide and switch arrangement changed
  • Search path Px.8412 or Px.8413 too short

First checks, in this order

  1. Check that the slide actually reaches the switch or end stop.
  2. Check the switch signal on the drive I/O status.
  3. Check the search path settings Px.8412 and Px.8413.

05 | 01 | 00056: Configuration of homing run invalid

Hits OEE: Availability

What it means: The homing settings do not fit together, for example a homing method to a limit switch without the switch configured. In the 1-part format it shows as 83951672; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 56.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.8450 (stop category 0, 1 or 2).

Likely causes

  • Homing method needs a limit switch that is not configured
  • Position encoder interface and referencing encoder interface differ

First checks, in this order

  1. Configure the limit switch the homing method needs.
  2. Set the position encoder interface (Px.122) and the referencing encoder interface (Px.101733) to the same interface when referencing of all encoders (Px.1214) is not active.

05 | 02 | 00067: Task ignored as referencing missing

Hits OEE: Availability

What it means: A motion command was refused because the axis has not been homed (referenced). In the 1-part format it shows as 84017219; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 67.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • Homing not run after power on
  • Homing lost after an encoder or motor change

First checks, in this order

  1. Run homing, then repeat the command.
  2. Make the PLC sequence home the axis before positioning moves.

08 | 04 | 00143: EtherCAT process data communication failed

Hits OEE: Availability

What it means: Cyclic EtherCAT process data stopped arriving at the drive. In the 1-part format it shows as 134480015; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 143.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • EtherCAT cable or connector unplugged or damaged
  • Master stopped or changed state
  • Wrong cable order at IN and OUT ports

First checks, in this order

  1. Check EtherCAT cables and connectors.
  2. Check the master state and its diagnostics.
  3. Check the EtherCAT LEDs on the drive for link and state.

08 | 03 | 00391: Process data communication failed

Hits OEE: Availability

What it means: Cyclic PROFINET process data communication between the PLC and the drive failed. In the 1-part format it shows as 134414727; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 391.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • PROFINET cable or connector problem
  • PLC stopped or connection dropped
  • Network overload or switch problem

First checks, in this order

  1. Check the PROFINET cables, connectors and switches.
  2. Check the PLC and its diagnostic buffer.
  3. Check the drive's PROFINET LEDs.

08 | 13 | 00394: Invalid process data

Hits OEE: Availability

What it means: The EtherNet/IP process data configuration is invalid. In the 1-part format it shows as 135070090; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 394.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • Assembly or connection settings in the scanner do not match the drive
  • Configuration changed in the PLC project

First checks, in this order

  1. Configure the EtherNet/IP interface again as described in the manual.
  2. Check the assembly sizes in the scanner configuration.

08 | 00 | 00140: Failure of fieldbus synchronisation signal

Hits OEE: Availability

What it means: The drive lost the fieldbus synchronisation signal used for cyclic synchronous modes. In the 1-part format it shows as 134217868; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 140.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.801 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Cable or connector fault
  • PLC synchronisation (distributed clock or isochronous mode) set wrong

First checks, in this order

  1. Check the fieldbus wiring.
  2. Check the PLC configuration for synchronisation.

08 | 04 | 00281: Process data not received at Sync time

Warning: act before it becomes a stop

What it means: EtherCAT process data did not arrive by the sync time. Festo notes that classification changes for this message are not saved permanently. In the 1-part format it shows as 134480153; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 281.[1][2]

Machine response: Default: warning (motion continues, status LED flashes yellow). Can be changed with Px.758 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Process data and sync time not matched in the controller
  • Master cycle jitter or overload

First checks, in this order

  1. Check the relation between process data and sync time in the controller configuration.
  2. Check master cycle time and load.

08 | 09 | 00299: Error Sign of Life

Hits OEE: Availability

What it means: Too many PROFIdrive sign of life signals from the PLC were missed. In the 1-part format it shows as 134807851; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 299.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • PLC not updating the sign of life counter correctly
  • PROFINET communication problems
  • Bus or PLC overloaded

First checks, in this order

  1. Check PROFINET communication.
  2. Check that the PLC sends the life sign correctly (trace STW2.12 to STW2.15 with trigger ZSW1.3).
  3. Check the allowed telegram failure rate (PNU 925).
  4. Check bus and PLC load.

08 | 09 | 00294: PLC Control is not set

Hits OEE: Availability

What it means: Over PROFIdrive, the PLC control bit is not set, so the drive does not accept control from the PLC. In the 1-part format it shows as 134807846; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 294.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Can be changed with Px.11280117 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Control word STW1 bit 10 not set by the PLC program

First checks, in this order

  1. Set the PLC control bit (STW1 bit 10) in the PLC program.

07 | 04 | 00136: Commutation finding failed

Hits OEE: Availability

What it means: The automatic search for the motor commutation angle did not succeed. In the 1-part format it shows as 117702792; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 136.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • Encoder not connected or giving invalid values
  • Vertical axis with load pulling during the search
  • Monitoring window or step size not suited to the axis

First checks, in this order

  1. Check the encoder connection and values.
  2. On vertical axes with load, reduce the load mass during the search.
  3. Enlarge the monitoring window Px.6693 or reduce the step size Px.664.
  4. Reduce the dynamic values Px.669, Px.6691 and Px.6692.

07 | 04 | 00137: Commutation finding direction error

Hits OEE: Availability

What it means: During the commutation angle search, the motor's direction of rotation did not match the position reported by the encoder. In the 1-part format it shows as 117702793; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 137.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • Motor shaft cannot turn freely (axis jammed or brake closed)
  • Encoder and motor direction settings do not match
  • Too little current injection for the search

First checks, in this order

  1. Check that the motor shaft turns freely and the axis is not jammed.
  2. Increase the current injection for commutation angle finding (Px.270).
  3. Adjust the dynamic values Px.669, Px.6691 and Px.6692.
  4. Check that encoder direction (P0.1171.0.0) and motor direction (Px.1172) match.

18 | 00 | 00092: Motor change detected, commutation angle invalid

Hits OEE: Availability

What it means: The drive detected a different motor than before, so the stored commutation angle is no longer valid. In the 1-part format it shows as 301989980; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 92.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • Motor replaced
  • Motor cable moved to another drive

First checks, in this order

  1. Run commutation angle finding and homing, then save the parameters.

18 | 03 | 00235: Incremental encoder analysis invalid

Hits OEE: Availability

What it means: General error on a quadrature (A/B) incremental encoder. In the 1-part format it shows as 302186731; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 235.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • Encoder cable damaged or poorly shielded
  • Signal levels outside the detection thresholds

First checks, in this order

  1. Check the encoder cable and shield connection.
  2. Adjust the detection thresholds P10053 and P10054 if needed.
  3. Restart the device.

18 | 01 | 00229: Common error EnDat 2.2

Hits OEE: Availability

What it means: General error on an EnDat 2.2 encoder connected to the CMMT-AS. In the 1-part format it shows as 302055653; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 229.[1]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • Encoder type set wrong in the configuration
  • Short circuit in the encoder power supply wiring
  • Encoder defective

First checks, in this order

  1. Check the encoder type configuration.
  2. Check the encoder cable for a short circuit in the supply lines.
  3. Replace the encoder if the error stays.

02 | 04 | 00042: Encoder supply voltage monitoring thresholds

Hits OEE: Availability

What it means: The CMMT-AS encoder supply voltage is outside its monitoring thresholds. In the 1-part format it shows as 33816618; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 42.[1]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • Encoder cable short circuit or damage
  • Encoder supply voltage set wrong for the encoder

First checks, in this order

  1. Check the encoder wiring.
  2. Check the encoder voltage supply setting.
  3. Contact Festo service if the drive output is faulty.

05 | 02 | 00066: Task ignored as encoder not ready

Hits OEE: Availability

What it means: A motion command was refused because the encoder is not ready. In the 1-part format it shows as 84017218; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 66.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • Encoder cable unplugged or damaged
  • Encoder supply missing

First checks, in this order

  1. Check the encoder cable.
  2. Check the voltage supply for the encoder.

07 | 02 | 00128: Velocity too high

Hits OEE: Availability

What it means: Speed monitoring found the motor turning faster than the maximum velocity allowed. In the 1-part format it shows as 117571712; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 128.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.4661 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Set velocity higher than the maximum velocity Px.4660
  • Wrong commutation offset angle causing a runaway

First checks, in this order

  1. Check the maximum velocity setting Px.4660.
  2. Reduce the set velocity.
  3. Check the offset angle and run commutation angle finding.

07 | 02 | 00129: Out of target range

Warning: act before it becomes a stop

What it means: The axis left the target window after it had reached its target position. In the 1-part format it shows as 117571713; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 129.[1][2]

Machine response: Default: warning (motion continues, status LED flashes yellow). Can be changed with Px.4669 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Load pushing the axis away from its position
  • Target window or settling time too tight
  • Weak position control at standstill

First checks, in this order

  1. Check the target range window and settling time (Px.4665 to Px.4667).
  2. Decide if this monitoring makes sense for the application; it can be switched off with Px.4669.

07 | 03 | 00135: Limit for velocity or current active

Warning: act before it becomes a stop

What it means: A velocity or current limit is active, so the drive cannot deliver what the setpoint asks. Often seen just before a following error. In the 1-part format it shows as 117637255; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 135.[1][2]

Machine response: Default: information (logged in the message list only). Can be changed with Px.52677 (warning, information or invalid).

Likely causes

  • Motion task too dynamic for the motor and drive
  • Velocity or current limits set low

First checks, in this order

  1. Reduce the dynamic values of the motion task.
  2. Check the velocity limits Px.850 and Px.851.
  3. Check the current limits Px.854 to Px.856.

07 | 03 | 00134: Voltage limitation active

Warning: act before it becomes a stop

What it means: The drive has reached its output voltage limit, so it cannot raise speed or torque further. In the 1-part format it shows as 117637254; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 134.[1][2]

Machine response: Default: information (logged in the message list only). Can be changed with Px.52682 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Speed too high for the available supply voltage
  • Torque demand too high at high speed

First checks, in this order

  1. Reduce velocity.
  2. Reduce torque demand.

05 | 02 | 00078: Stop ramp: Timeout

Hits OEE: Availability

What it means: The axis did not come to standstill within the time allowed for the stop ramp. In the 1-part format it shows as 84017230; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 78.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • Standstill monitoring set too tight
  • Load or mechanics keep the axis moving after the ramp

First checks, in this order

  1. Check the standstill monitoring settings Px.4610 and Px.468.

05 | 02 | 00064: Task ignored as DC link coupling not ready

Hits OEE: Availability

What it means: A motion command was refused because DC link voltage is missing or not yet detected. In the 1-part format it shows as 84017216; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 64.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • Mains or DC supply not switched on
  • Braking resistor missing where it is required

First checks, in this order

  1. Check that the mains voltage is present.
  2. When a DC power supply is used, check the DC voltage after it switches on.
  3. Check that a braking resistor is connected if one is required.

05 | 02 | 00283: Brake test failed

Hits OEE: Availability

What it means: The holding brake test failed: the axis moved more than allowed while the brake was closed and torque was applied. In the 1-part format it shows as 84017435; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 283.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Can be changed with Px.103138 (stop category 0, 1 or 2, warning, information or ignore).

Likely causes

  • Worn holding brake
  • Monitoring window for travel during the test set wrong

First checks, in this order

  1. Check the holding brake for wear and replace it if needed.
  2. Check the monitoring window stroke Px.103117.x.0.

10 | 01 | 00156: Common error power output stage

Hits OEE: Availability

What it means: The power output stage reports an internal error. In the 1-part format it shows as 167837852; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 156.[1][2]

Machine response: Default: error, stop category 0 (power stage off at once, the holding brake closes, an axis without brake coasts down). Fixed, cannot be changed.

Likely causes

  • Internal hardware fault in the drive

First checks, in this order

  1. Restart the device.
  2. If the error comes back, contact Festo service.

13 | 02 | 00217: Auto tuning aborted

Hits OEE: Availability

What it means: The auto tuning run in Festo Automation Suite was aborted. In the 1-part format it shows as 218235097; where only 16 bits are sent (for example PROFINET fault buffer PNU 947) it is 217.[1][2]

Machine response: Default: error, stop category 1 (the axis ramps down on the stop ramp, then the brake closes and the controller switches off). Fixed, cannot be changed.

Likely causes

  • Another error occurred during auto tuning
  • Movement during tuning blocked or limited

First checks, in this order

  1. Check for other messages in the message list and fix their cause.
  2. Start auto tuning again.

Log it, or the same alarm comes back

An error stops the axis, and on an assembly or packaging machine one axis stops the machine, so in OEE terms it is a breakdown. Log the message, the axis and the minutes lost.

  • Reason code: the message plus the axis, for example CMMT-AS following error, pick and place Y axis, so an error that trips on the same move shows up as a pattern.
  • Loss bucket: a stop that needs a reset, a part or a technician is an availability loss (breakdown). Stops shorter than your micro-stop threshold go to performance (minor stops). The six big losses page shows where each one belongs.
  • What to count: how often each code fires per week and the minutes it costs. Two numbers a week turn "that alarm comes up sometimes" into a ranked list. The MTBF and MTTR calculator and the downtime cost calculator do the math.

The free OEE tracker logs each stop with its reason and turns the week into a downtime Pareto, so the code that costs the most rises to the top.

fabrico.io has a guide to servo motor failure symptoms. A code tells you what the machine detected, not what happened on the line in the seconds before. Fabrico's camera-based OEE software syncs camera video with machine data, so you can replay the moment the axis stopped next to the drive's error.

Frequently asked questions

What does a following error mean on a Festo CMMT-AS?

It means the axis did not keep up with its setpoint. The drive compares setpoint and actual values all the time while the axis is moving to its target. If the difference stays outside the monitoring window for longer than the damping time, it raises 07 | 02 | 00126 (position) or 07 | 02 | 00127 (velocity), and by default stops the axis with stop category 1. Typical causes are too much speed or acceleration for the load, stiff or jammed mechanics, a dragging brake, the drive running into its current limit, or a window that is set too tight. Trace the move in Festo Automation Suite before you widen the window.

What is the difference between position and velocity following error on a CMMT?

Position following error (07 | 02 | 00126) watches the distance between setpoint and actual position, against the window Px.463 and damping time Px.462; the live value is Px.4682. Velocity following error (07 | 02 | 00127) watches the difference between setpoint and actual speed, against the window Px.464 and damping time Px.4690; the live value is Px.4683. Newer firmware also has an acceleration following error (07 | 02 | 00658). A velocity following error often points to acceleration that is too high; a position following error that builds slowly often points to friction, load or a tight window.

How do I acknowledge an error on a Festo CMMT?

Fix the cause first: an active message cannot be acknowledged, only a cancelled one. Then acknowledge with a rising edge on the ERR-RST digital input, over the fieldbus (CiA 402 control word bit 7 Fault reset, or PROFIdrive STW1.7 from 0 to 1), with Acknowledge All in the Festo Automation Suite plug-in (it needs master control), through the web server, or with Acknowledge all on the CDSB operator unit. Serious errors cannot be acknowledged at all; switch the drive off and on, and call Festo service if the error comes back at once.

How do I read a Festo CMMT error number like 07 | 02 | 00126 or 117571710?

Festo writes each diagnostic message as main group, subgroup and error number. In 07 | 02 | 00126, 07 is monitoring, 02 is motion monitoring and 00126 is the position following error. The same message can also show as one decimal number: combine the groups as hex bytes (07, 02, 007E) and convert, which gives 117571710. Fieldbus channels that only carry 16 bits, such as the PROFINET fault buffer PNU 947, give only the error number, here 126. A D0 prefix means a system message, D1 a message for axis 1.

Where is the Festo CMMT error list as a PDF?

The full list is in chapter 9.4.6, Diagnostic messages with information for fault clearance, of the manual Software, Function, Fieldbus, Device profile. For the CMMT-AS-...-S1 it is Festo document 8259155 (edition 2026-06p); for the CMMT-ST it is 8259159 (edition 2026-06o). Both are on the Festo support portal. Each entry gives the message number, name, remedy, default reaction and the parameter that changes the reaction.

Sources

Codes and meanings follow the manufacturer documentation below. Wording is ours, simplified for the shop floor; the manual for your exact model and software version wins if it differs.

  1. CMMT-AS-...-S1 Servo drive, Manual: Software, Function, Fieldbus, Device profile, Festo document 8259153 [8259155], edition 2026-06p, hosted by Festo (festo.com support portal)
  2. CMMT-ST Servo drive, Manual: Software, Function, Fieldbus, Device profile, Festo document 8259157 [8259159], edition 2026-06o, hosted by Festo (festo.com support portal)
  3. CMMT-AS-C2/3/5-11A-P3-...-S1 Servo drive, Operating instruction: Installation, Safety sub-function, Festo document 8215506 [8215508], edition 2024-05f, hosted by Festo (festo.com support portal)
  4. CMMT-ST-C8-1C-EC/EP/PN-S0 Servo drive, Operating instruction: Installation, Safety sub-function, Festo document 8214097 [8214099], edition 2024-04d, hosted by Festo (festo.com support portal)
  5. CMMT-AS-C2/4-3A-... Servo drive, Manual: Assembly, Installation, Festo document 8183880 [8183882], edition 2023-07f, hosted by Festo (festo.com support portal)
  6. CMMT-AS Servo drive, Manual: Software, Function, Fieldbus, Device profile, Festo document 8186190 [8186192], edition 2022-11j, hosted by Festo (festo.com support portal)
  7. CMMT-ST Servo drive, Manual: Software, Function, Fieldbus, Device profile, Festo document 8186197 [8186199], edition 2022-11i, hosted by Festo (festo.com support portal)

See the moment the axis stopped

Fabrico, a light MES with computer vision, syncs camera footage with machine and timeline data, so you can replay the exact moment the axis stopped and review the cause next to the drive's error. Cameras also catch short stops and a line that is switched on but not producing, the losses nobody writes down. Machines connect through a PLC, a Fabrico IoT device or an AI camera.

Book a Fabrico demo
The lookup stays free.

Related: Lexium 32 errors · B&R ACOPOS errors · Kollmorgen AKD fault codes · servo drive troubleshooting · servo motor

Other alarm code lookups: FANUC: servo amplifier · spindle amplifier · robot SRVO | Siemens: MICROMASTER 440 · MASTERDRIVES · SINAMICS G120 · SINAMICS V90 servo · SINAMICS V20 | ABB: ACS550 drive · ACS800 drive · robot IRC5 | Okuma: OSP alarms | Haas: alarm lookup | Mitsubishi: MELSERVO servo · FR-D700 and FR-E700 inverters · FX PLC | Allen-Bradley: Kinetix and Ultra3000 · MicroLogix · PowerFlex 753 and 755 · PowerFlex 70 and 700 · 1336 and 1305 | Yaskawa: V1000 drive · SERVOPACK servo · Motoman robot | Delta: VFD drives · ASDA servo | Eaton: DC1 and SVX9000 drives | Control Techniques: Commander SK and M200 | Kollmorgen: AKD servo | Lenze: SMVector, 8200, 8400, i500 | Magnetek: IMPULSE and DSD 412 | Omron: MX2 and RX inverters · G5 and 1S servo · CP1 and CJ2 PLC | WEG: CFW500, CFW300, CFW11, CFW08 | Hitachi: WJ200 inverter · SJ700 and SJ-P1 | Toshiba: E3, Q9, P9, S15, nC3, AS3 | AutomationDirect: GS10, GS20, GS4, GS1 to GS3 | Videojet: 1000 Line CIJ printers | Lincoln Electric: Power Wave welders | Pilz: PNOZ safety relays | SICK: S3000, S300, microScan3 | SANYO DENKI: SANMOTION servo | Parker: SSD 590+, 690+, AC10 | KEB: COMBIVERT F5 | Epson: robot RC700, RC90 | B&R: ACOPOS servo | Schneider Electric: Lexium 32 servo | Bosch Rexroth: IndraDrive | Vacon: NX, VACON 100 and 20 | Fuji Electric: FRENIC-Mini, Multi, Ace, MEGA | LS Electric: S100, G100, iG5A | Panasonic: MINAS A6 and A5 servo | Invertek: Optidrive E3, P2, Eco | SEW-Eurodrive: MOVITRAC B and MOVIDRIVE B

Related tools: full troubleshooting directory · OEE calculator · downtime cost · MTBF / MTTR · glossary

OEE essentials: OEE calculator · What is OEE · How to improve OEE · Six big losses · Availability · TEEP · Cost of downtime · OEE benchmark · Free OEE tracker · Free OEE software · How to track downtime · How to implement OEE · Light MES vs full MES