Delta ASDA Servo Alarm Codes

AL001: Over current

What it means: Main circuit output current shot above 1.5 times the allowed instantaneous current, so the drive switched the servo off to protect the power stage.^[1][2][3][4]

Drive response: ALM, servo off. A2 and B2: clear with DI.ARST. A3 and B3: power cycle.

Likely causes

• Short circuit on the drive output U, V, W or in the motor cable
• Motor power wiring connected in the wrong order
• Damaged IGBT power stage inside the drive

First checks, in this order

1. With power off and the CHARGE lamp out, check the U, V, W cable and motor for shorts and exposed conductors.
2. Compare the U, V, W wiring order with the wiring chapter of the manual.
3. If the wiring is good and the heat sink temperature reads abnormal, send the drive to Delta or the distributor.
4. A3 and B3: if gains were raised far above default, reset parameters to factory values and raise them step by step.

AL002: Over voltage

What it means: Main circuit voltage is above the drive's rated limit.^[1][2][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Supply voltage higher than the drive rating
• Wrong supply system for this drive model
• Regenerative resistor missing, wrong size, or P1-52 / P1-53 set wrong (listed by A2, A3, B3)
• Drive hardware fault

First checks, in this order

1. Measure the main supply at R, S, T with a voltmeter and compare with the drive rating.
2. Confirm the supply system matches the drive; fit the right source or a regulator or transformer.
3. Check the regenerative resistor wiring and set P1-52 (resistance) and P1-53 (capacity) correctly.
4. If the supply reads normal and the alarm stays, send the drive for repair.

AL003: Under voltage

What it means: Main circuit voltage dropped below the rated minimum. Delta flags it on the WARN output, but the servo switches off.^[1][2][3][4]

Drive response: WARN output, servo off. A2 and B2: power cycle, or automatic with P2-66 Bit 2. A3 and B3: DI.ARST after voltage recovers, or automatic with P2.066 Bit 2 = 1.

Likely causes

• Low supply voltage
• Main circuit power off while control power stays on
• Wrong supply system for the drive

First checks, in this order

1. Check the main circuit input wiring at R, S, T.
2. Measure the main circuit voltage and check the main power switch or breaker.
3. Confirm the supply system matches the drive specification.
4. To have it clear by itself once voltage is back, set P2-66 Bit 2 (A2, B2) or P2.066 Bit 2 (A3, B3). On A3 and B3, P2.066 Bit 9 = 1 turns it into a full alarm.

AL004: Motor Combination Error

What it means: The drive reads a motor and encoder that do not match it.^[1][2][3][4]

Drive response: ALM, servo off; clear by power cycle.

Likely causes

• Wrong motor model connected to this drive
• Loose encoder connector
• Damaged encoder

First checks, in this order

1. Confirm the motor model is one Delta pairs with this drive.
2. Reseat the encoder plug at CN2 and at the motor.
3. If the encoder is faulty, replace the motor.

AL005: Regeneration Error

What it means: The regeneration (braking energy) control has an error.^[1][2][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Wrong regenerative resistor fitted, or the external resistor is not connected
• P1-53 not set to 0 while no regenerative resistor is used
• P1-52 or P1-53 set wrong

First checks, in this order

1. Check the regenerative resistor wiring.
2. Recalculate the resistor needed and set P1-52 (resistance) and P1-53 (capacity) to match it.
3. Set P1-53 to 0 if no regenerative resistor is used.
4. If it stays, send the drive to Delta or the distributor.

AL006: Overload

What it means: The motor and drive have run above their rated load for too long.^[1][2][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Continuous load above rating
• Gains too high causing vibration, or acceleration and deceleration set too fast
• U, V, W or encoder wiring wrong
• Faulty motor encoder

First checks, in this order

1. Set P0-02 to 12 to show the average load; if it stays above 100%, reduce the load or use a larger motor.
2. Look for mechanical vibration and lower the control gains if needed.
3. Lengthen the acceleration and deceleration times.
4. Check the U, V, W and encoder wiring.

AL007: Over speed (B2); Overspeed (A2); Excessive deviation of Speed command (A3, B3)

What it means: The gap between commanded speed and actual motor speed went past the limit set in P2-34. Despite the A2 and B2 name, it is a speed following error, so a torque limit can cause it as well as a real overspeed.^[1][2][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Sudden step or spike in the analog speed command
• P2-34 (allowed speed deviation) set too small
• Torque limit active (DI.TRQLM, P1-02, P1-12 to P1-14) so the motor cannot follow
• Wrong motor power or encoder wiring (listed by A3, B3)

First checks, in this order

1. Scope the analog speed command for spikes; soften the command or turn on the input filter.
2. Check P2-34.
3. Check whether DI.TRQLM is on, whether P1-02 enables the torque limit, and set P1-12 to P1-14 to 100% if no limit is wanted.
4. Check the motor power cable and encoder cable wiring.

AL008: Abnormal Pulse Command

What it means: The position pulse command arrives faster than the drive's pulse input hardware accepts.^[1][2][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Controller pulse frequency above the input rating (B2 spec: 500 kpps low-speed or 4 Mpps high-speed line driver, 200 kpps open collector)

First checks, in this order

1. Scope the pulse input and compare the frequency with the drive's rated input frequency.
2. Set the controller's pulse output within the rating of the input you are wired to.

AL009: Excessive Deviation of Position Command

What it means: Position following error (commanded position minus actual position) went past the limit set in P2-35.^[1][2][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• P2-35 set too low
• Position gain too low
• Torque limit or speed limit too low
• Load too heavy or the mechanism is binding
• Electronic gear P1-44 / P1-45 set wrong (listed by A2, A3, B3)
• Loose power cable or maximum speed limit P1-55 too low (listed by A3, B3)

First checks, in this order

1. Check P2-35 and raise it if it is too tight for the machine.
2. Check that the gains suit the load.
3. Check the torque and speed limits (P1-02, P1-09 to P1-11, P1-12 to P1-14).
4. Check the mechanism for binding, then the load against motor size.
5. Check the electronic gear ratio P1-44 / P1-45 and the maximum speed P1-55.

AL010: Voltage error during regeneration

What it means: During braking the DC bus voltage stayed at about 400 V for too long.^[1][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Wrong or unconnected external regenerative resistor
• P1-53 not set to 0 while no regenerative resistor is fitted

First checks, in this order

1. Check the regenerative resistor wiring and recalculate the resistor size.
2. Set P1-52 and P1-53 to match the resistor, or P1-53 to 0 if none is used.
3. If it stays, send the drive to Delta.

AL011: Encoder Error (A2, B2); CN2 communication failed (A3, B3)

What it means: The drive lost a good signal from the motor encoder on connector CN2.^[1][2][3][4]

Drive response: ALM, servo off; clear by power cycle.

Likely causes

• Encoder cable wired wrong
• Loose CN2 plug or motor-side encoder plug
• Damaged encoder cable or poor connection
• Electrical noise cutting the encoder link (listed by A3, B3)
• Damaged encoder
• Motor model not supported by the drive (listed by A3, B3)

First checks, in this order

1. Check the encoder wiring against the manual.
2. Reseat the CN2 plug and the encoder plug at the motor.
3. Inspect the encoder cable for crushed or broken wires.
4. A3 and B3: set P0-02 to -80 to watch the encoder communication error count; if it keeps rising, ground the motor (green wire to the drive heat sink), route the encoder cable away from power cables and use shielded cable.
5. If every check passes, replace the motor.

AL012: Adjustment Error (A2, B2); Calibration error (A3)

What it means: During the drive's electrical self calibration a measured value came out of range.^[1][2][3]

Drive response: ALM, servo off; clear by removing the CN1 wiring and running auto adjustment.

Likely causes

• Analog input not at zero during calibration (signal present on CN1)
• Damaged detection circuit in the drive

First checks, in this order

1. Measure the analog input terminals; they should sit at ground potential.
2. Remove the CN1 cable and run the auto adjustment again.
3. Cycle power; if it returns, send the drive in.

AL013: Emergency Stop

What it means: The emergency stop input DI.EMGS is active. Delta flags it on the WARN output, but the servo switches off.^[1][2][3][4]

Drive response: WARN output, servo off; clears by itself once DI.EMGS turns off.

Likely causes

• E-stop pressed or the safety chain is open
• EMGS input is normally closed (contact B) and its circuit is open, for example an unwired DI8, which is EMGS by default on B2
• EMGS assigned to a digital input by mistake

First checks, in this order

1. Release the E-stop and check the E-stop circuit.
2. Find the input set to EMGS (code 21) in P2-10 to P2-17 or P2-36; on B2 it is DI8 (P2-17) by default.
3. Match the contact type to the wiring: 0x0021 is normally closed, 0x0121 normally open.
4. If no E-stop is wired to the drive, set that input to another function or 0.

AL014: Reverse Limit Error (A2, B2); Negative limit error (A3, B3)

What it means: The reverse (negative) limit input NL is active, so motion in that direction is blocked while the servo stays on.^[1][2][3][4]

Drive response: WARN, servo stays on. A2 and B2: DI.ARST, Servo Off, or move the axis back. A3 and B3: clears once the motor moves off the limit.

Likely causes

• Axis has reached the reverse limit switch
• NL input is normally closed and its circuit is open, for example an unwired DI6, which is NL by default on B2
• Unstable servo tuning or inertia ratio making the axis overshoot

First checks, in this order

1. Check the limit switch and its wiring.
2. On B2, DI6 (P2-15) is NL by default and must stay closed; if no limit switch is used, change P2-15 (code 22 normally closed, 0x0122 normally open, or 0 to disable).
3. Check the gain settings and inertia ratio.

AL015: Forward Limit Error (A2, B2); Positive limit error (A3, B3)

What it means: The forward (positive) limit input PL is active, so motion in that direction is blocked while the servo stays on.^[1][2][3][4]

Drive response: WARN, servo stays on. A2 and B2: DI.ARST, Servo Off, or move the axis back. A3 and B3: clears once the motor moves off the limit.

Likely causes

• Axis has reached the forward limit switch
• PL input is normally closed and its circuit is open, for example an unwired DI7, which is PL by default on B2
• Unstable servo tuning or inertia ratio making the axis overshoot

First checks, in this order

1. Check the limit switch and its wiring.
2. On B2, DI7 (P2-16) is PL by default and must stay closed; if no limit switch is used, change P2-16 (code 23 normally closed, 0x0123 normally open, or 0 to disable).
3. Check the gain settings and inertia ratio.

AL016: IGBT Overheat (A2, B2); Abnormal IGBT temperature (A3, B3)

What it means: The drive's IGBT power stage is too hot.^[1][2][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Continuous load above the drive rating
• Short circuit on the drive output

First checks, in this order

1. Check for overload or high motor current; reduce the load or use a larger motor and drive.
2. Check the drive output wiring for shorts.

AL017: Abnormal EEPROM (A2, B2); EEPROM error (A3, B3)

What it means: The DSP hit an error reading or writing its parameter memory (EEPROM).^[1][2][3][4]

Drive response: ALM, servo off. At power up: reset parameters, then power cycle. During operation: DI.ARST.

Likely causes

• A parameter value out of range at power up
• Write error while saving a parameter during operation
• Wrong drive type in a hidden parameter (panel shows E100X)
• Damaged or empty ROM data (panel shows E0001)

First checks, in this order

1. Press SHIFT on the panel to read the code EXGAB: G is the parameter group and AB the parameter number in hex (E320A means P2-10, E3610 means P6-16).
2. Correct that parameter, then cycle power.
3. If it shows E100X or E0001, send the drive to Delta or the distributor.

AL018: Abnormal signal output (B2); Encoder output error (A2); OA and OB output error (A3, B3)

What it means: The encoder pulse output to the controller (OA, OB) is above the hardware's maximum output frequency.^[1][2][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Output resolution P1-46 too high for the motor speed
• An encoder alarm (AL011, AL024, AL025, AL026) upsetting the output
• Noise or cable damage (listed by A3, B3)

First checks, in this order

1. Check the alarm history P4-00 to P4-04 for encoder alarms and fix those first.
2. Set P1-76 above the highest motor speed and keep (motor speed / 60) x P1-46 x 4 below 19.8 x 10^6.
3. A3 and B3: if the OA and OB outputs are unused, P2-65 Bit 13 = 1 turns off AL018 and AL048 detection.

AL019: Serial Communication Error

What it means: RS-232 or RS-485 (Modbus) communication with the drive has an error.^[1][2]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Communication settings do not match the master
• Wrong drive address
• Master reading or writing a wrong register or value

First checks, in this order

1. Check P3-00 (address), P3-01 (baud rate) and P3-02 (protocol) against the master.
2. Check the register address and the value the master writes.

AL020: Serial Communication Time Out

What it means: The drive received no RS-232 or RS-485 command within the communication timeout.^[1][2][3][4]

Drive response: WARN, servo stays on; clear with DI.ARST.

Likely causes

• Timeout parameter P3-04 set too short
• Master stopped polling, or the cable is loose or broken

First checks, in this order

1. Check P3-04 (communication timeout).
2. Check the communication cable and connectors.

AL022: Main Circuit Power Lack Phase (A2, B2); RST power error (A3, B3)

What it means: A phase of the main supply R, S, T is missing or loose. Delta flags it on the WARN output, but the servo switches off.^[1][2][3][4]

Drive response: WARN output, servo off; clear with DI.ARST.

Likely causes

• Loose R, S, T cable
• Lost phase or main power off
• On A2, A3 and B3 drives of 1.5 kW and below it trips when all three phases are missing; on 2 kW and above when one phase is missing

First checks, in this order

1. Check the R, S, T cable and terminals for a loose or missing phase.
2. Measure all three phases at the drive.
3. If the supply is good and it stays, send the drive in.
4. A3 and B3: P2-66 Bit 12 = 1 turns it into a full alarm.

AL023: Early Warning for Overload (A2, B2); Early overload warning (A3, B3)

What it means: Load is close to the overload trip level set in P1-56; the servo keeps running.^[1][2][3][4]

Drive response: WARN, servo stays on; clear with DI.ARST.

Likely causes

• Machine running near overload
• P1-56 (overload warning level) set too low

First checks, in this order

1. Check the load as for AL006.
2. Raise P1-56, or set it above 100 to switch the warning off.

AL024: Encoder initial magnetic field error

What it means: The encoder's U, V, W commutation signals at start up are wrong.^[1][2][3][4]

Drive response: ALM, servo off; clear by power cycle.

Likely causes

• Electrical noise on the encoder signal
• Poor motor grounding
• Encoder fault

First checks, in this order

1. Check the motor ground: the green ground of the power cable goes to the drive heat sink.
2. Route the encoder cable away from power and high-current cables.
3. Use shielded encoder cable with the shield grounded.
4. If it stays, send the motor to Delta or the distributor.

AL025: The Internal of the Encoder is in Error (A2, B2); Encoder internal error (A3, B3)

What it means: The encoder's internal memory and counter are in error.^[1][2][3][4]

Drive response: ALM, servo off; clear by power cycle.

Likely causes

• Electrical noise or poor grounding
• Motor shaft turning at power up from inertia or load (listed by A2, A3, B3)
• Encoder fault

First checks, in this order

1. Ground the motor: green ground of the UVW cable to the drive heat sink.
2. Separate the encoder cable from power cables and use shielded cable.
3. Make sure the shaft is still when power is switched on.
4. If it stays, send the motor in.

AL026: Unreliable internal data of the encoder (A2, B2); Encoder unreliable internal data (A3, B3)

What it means: The drive read bad encoder data three times in a row.^[1][2][3][4]

Drive response: ALM, servo off; clear by power cycle.

Likely causes

• Electrical noise or poor grounding
• Encoder hardware fault

First checks, in this order

1. Ground the motor and separate the encoder cable from power cables.
2. Use shielded encoder cable with the shield grounded.
3. A3 and B3: watch the error count with P0-02 = -80; if it stays at 0 and the alarm repeats, send the motor in.

AL027: The Internal of the Encoder is in Error (B2); The Internal of the Motor is in Error (A2); Encoder internal reset error (A3, B3)

What it means: The encoder reset itself unexpectedly (internal reset error).^[1][2][3][4]

Drive response: ALM, servo off; clear by power cycle.

Likely causes

• Loose encoder cable
• Unstable encoder supply
• Encoder hotter than 95 °C (listed by A2, A3, B3)
• Noise or poor grounding

First checks, in this order

1. Check the encoder cable and plugs are tight.
2. Use shielded encoder cable and check the encoder supply is stable.
3. Check the motor temperature; let it cool before restarting.
4. If it stays, send the motor in.

AL028: The Internal of the Encoder is in Error

What it means: On ASDA-B2, AL028 means the encoder's U, V, W signals are in error.^[1]

Drive response: ALM, servo off; clear by power cycle.

Likely causes

• Electrical noise or poor grounding
• Encoder fault

First checks, in this order

1. Ground the motor: green ground of the UVW cable to the drive heat sink.
2. Separate the encoder cable from power cables and use shielded cable.
3. If it stays, send the motor in.

AL028: Encoder voltage error or the internal of the encoder is in error (A2); Battery voltage error or encoder internal error (A3, B3)

What it means: On ASDA-A2, A3 and B3, AL028 means the absolute encoder battery voltage is above 3.8 V or the encoder signal is in error.^[2][3][4]

Drive response: ALM, servo off; clear by power cycle.

Likely causes

• Drive 5 V is charging the battery through a wiring error (for example CN2 pin 1 tied to BAT+)
• Wrong battery or battery installed wrong
• Encoder internal fault, noise or poor grounding

First checks, in this order

1. Check the battery and encoder wiring for a charging path from the drive.
2. Check the battery type and voltage (alarm above 3.8 V).
3. Ground the motor and separate and shield the encoder cable.
4. If it stays, send the drive and motor in.

AL029: The Internal of the Encoder is in Error

What it means: On ASDA-B2, AL029 means the encoder's internal address is in error.^[1]

Drive response: ALM, servo off; clear by power cycle.

Likely causes

• Electrical noise or poor grounding
• Encoder fault

First checks, in this order

1. Connect the ground of the UVW connector (green) to the drive heat sink.
2. Separate the encoder cable from power cables and use shielded cable.
3. If it stays, send the motor in.

AL029: Gray code error

What it means: On ASDA-A2, A3 and B3, AL029 means the absolute position within one revolution is in error.^[2][3][4]

Drive response: ALM, servo off; clear by power cycle.

Likely causes

• Absolute encoder single-turn data fault

First checks, in this order

1. Cycle power, run the motor and see whether the alarm comes back.
2. If it repeats, replace the encoder (motor).

AL02D: Encoder not responding

What it means: The encoder does not answer the drive.^[1]

Drive response: ALM, servo off; clear by power cycle.

Likely causes

• Encoder cable fault or loose plug
• Electrical noise or poor grounding
• Encoder fault

First checks, in this order

1. Connect the ground of the UVW connector (green) to the drive heat sink.
2. Separate the encoder cable from power cables and use shielded cable.
3. If it stays, send the drive or motor in.

AL030: Motor Crash Error (A2, B2); Motor collision error (A3, B3)

What it means: Motor torque reached the hard-stop level in P1-57 for longer than the time in P1-58, which the drive reads as a crash.^[1][2][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Axis really hit something or jammed
• Crash protection switched on by mistake (P1-57 not 0)
• P1-57 set too low or P1-58 too short for the normal load

First checks, in this order

1. Check the machine for a collision or jam.
2. If the protection is not wanted, set P1-57 to 0.
3. Set P1-57 from the real working torque: too low gives false trips, too high loses the protection.

AL031: Incorrect wiring of the motor power line U, V, W, GND (A2, B2); Motor power cable wiring error (A3, B3)

What it means: The motor power cable U, V, W or ground is wired wrong or an open circuit was detected.^[1][2][3][4]

Drive response: ALM, servo off. B2, A3, B3: power cycle. A2: DI.ARST.

Likely causes

• U, V, W phases swapped or a phase not connected
• Broken motor power cable
• Ground wire missing

First checks, in this order

1. Check U, V, W and GND against the wiring chapter and make sure the motor is grounded.
2. Check the cable for a broken conductor.
3. Detection switch: A2 uses P2-65 Bit 9 (off by default), A3 and B3 use P2-65 Bit 8 (on by default).

AL034: Internal communication of the encoder is in error (A2); Encoder internal communication error (A3, B3)

What it means: Communication inside the absolute encoder (or another encoder type) failed.^[2][3][4]

Drive response: ALM, servo off; clear by power cycle.

Likely causes

• Battery cable wired wrong or loose
• Battery voltage out of range
• Absolute encoder fault

First checks, in this order

1. Check the battery wiring, reconnect it and cycle power.
2. Measure the battery voltage.
3. If it stays, replace the motor.

AL035: Encoder temperature exceeds the protective range (A2, B2, B3); Temperature of the encoder or external sensor exceeds the protective range (A3)

What it means: Encoder temperature passed its protective limit: 100 °C in the A2, A3 and B3 manuals, 120 °C (motor above 105 °C) in the B2 manual.^[1][2][3][4]

Drive response: ALM, servo off; let it cool below the limit, then power cycle.

Likely causes

• Motor overloaded or poorly cooled
• High ambient temperature
• On A3, an external temperature sensor on CN5 over its limit (PM.022, PM.024)

First checks, in this order

1. Read the encoder temperature: P0-02 = 120 on A2, P0-02 = -124 on A3 and B3.
2. Improve cooling or reduce the duty.
3. If the encoder runs more than 30 °C hotter than the motor, send the motor in.
4. A3 without an external sensor: set PM.022 to 0.

AL040: Excessive Deviation of Full Closed-loop Position Control (A2); Excessive position error of full-closed loop control (A3)

What it means: In full closed-loop mode, the gap between motor encoder and external scale position went past the limit in P1-73.^[2][3]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• P1-73 set too low
• Loose encoder or scale connector, or slip between motor and mechanism
• On A3, non-integer scale pulses per motor turn adding up (P1-85 not set)

First checks, in this order

1. Check P1-73 and raise it if too tight.
2. Check the scale and encoder connectors and the coupling between motor and mechanism.
3. A3: check P1-85.

AL041: Communication of linear scale is breakdown (A2); CN5 is disconnected (A3)

What it means: Communication with the linear scale (auxiliary feedback on CN5) is lost.^[2][3]

Drive response: ALM, servo off. A2: DI.ARST. A3: power cycle.

Likely causes

• Scale cable or CN5 connection broken
• Full closed-loop feedback enabled while no scale is connected

First checks, in this order

1. Check the linear scale and the CN5 wiring.
2. A3: if CN5 is not used, set P1-74.X and PM.003.U to 0.

AL042: Analog input voltage error (A2); Voltage input for analog Speed command is too high (A3, B3)

What it means: The analog speed command voltage is above the level set in P1-83.^[2][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Analog command source too high or faulty
• P1-83 set below the normal command level

First checks, in this order

1. Measure all analog input voltages and check the speed command source.
2. Check P1-83; on A3 and B3 set it to 0 if this check is not needed.

AL044: Warning of servo drive function overload (A2); Servo function operational warning (A3, B3)

What it means: The drive's processor is overloaded by too many active functions, which can upset motion control such as PR or E-Cam.^[2][3][4]

Drive response: WARN, servo stays on; set P2-66 Bit 4 = 1 and power cycle to clear.

Likely causes

• Too many filters or control functions enabled at once

First checks, in this order

1. Switch off filters and functions that are not needed (A3 lists low-pass, moving and notch filters, vibration suppression, friction compensation, P1-57).
2. To hide the warning, set P2-66 Bit 4 to 1 and cycle power.

AL045: Wrong setting of E-gear ratio (A2); E-Gear ratio value error (A3, B3)

What it means: At power up the electronic gear ratio (P1-44 / P1-45) is outside the allowed range: 1/50 to 25600 on A2, 1 to 262144 on A3 and B3.^[2][3][4]

Drive response: ALM, servo off; clears after the setting is corrected and power is cycled.

Likely causes

• P1-44 or P1-45 set to an out-of-range ratio

First checks, in this order

1. Check P1-44 and P1-45 and bring the ratio into range.
2. Cycle power after correcting it.

AL048: Excessive encoder output error (B2); Encoder output error (A2); OA and OB output error (A3, B3)

What it means: The encoder pulse output (OA, OB) has errors or runs above the hardware's output frequency.^[1][2][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Encoder alarm (AL011, AL024, AL025, AL026) upsetting the output
• Output resolution P1-46 too high for the motor speed
• Noise or cable damage (listed by A3, B3)

First checks, in this order

1. Check the alarm history P4-00 to P4-04 for encoder alarms and fix those first.
2. Set P1-76 above the highest motor speed and keep (motor speed / 60) x P1-46 x 4 below 19.8 x 10^6.
3. A3 and B3: P2-65 Bit 13 = 1 turns off AL018 and AL048 detection when OA and OB are unused.

AL060: The absolute position is lost (A2); Absolute position is lost (A3, B3)

What it means: The absolute encoder lost its stored turn count because battery backup failed, so the absolute origin must be set again.^[2][3][4]

Drive response: WARN, servo stays on. A2: power cycle after the fix. A3 and B3: clears once the absolute origin is set again.

Likely causes

• Battery voltage low (below 2.8 V in the A2 manual, 2.9 V in A3 and B3)
• Battery changed while the drive was switched off (main power in the A2 and A3 manuals, control power in B3)
• Absolute function enabled before a battery was fitted
• Loose or broken battery circuit

First checks, in this order

1. Measure the battery and replace it with the drive powered on.
2. Check the wiring between the battery box and the drive, and the encoder cable.
3. Run homing to set the absolute origin again.

AL061: Encoder under voltage

What it means: The absolute encoder battery is below 3.1 V; the position is still held, but the battery needs changing.^[2][3][4]

Drive response: WARN, servo stays on; clears by itself after the battery is replaced.

Likely causes

• Battery running low

First checks, in this order

1. Measure the battery voltage (A3 and B3 can also read it on the panel).
2. Replace the battery while the drive is powered (main power on A2 and A3, control power on B3) so the position is kept.

AL062: The multi-turn of absolute encoder overflows (A2); Number of revolutions of the absolute encoder overflows (issued by encoder) (A3, B3)

What it means: The absolute motor has turned past the counter range of -32768 to +32767 revolutions.^[2][3][4]

Drive response: WARN, servo stays on; clear by power cycle.

Likely causes

• Axis keeps turning one way (conveyor or rotary table) beyond the turn counter

First checks, in this order

1. Check the number of turns the axis makes in operation.
2. Set the absolute origin again (homing).

AL067: Encoder temperature warning

What it means: On ASDA-B2 the encoder is above 100 °C (motor above 85 °C) but still within its protective range; the B2 table lists it on the ALM output with the servo off.^[1]

Drive response: ALM, servo off; clears when the temperature is back to normal.

Likely causes

• Motor running hot from load or poor cooling
• High ambient temperature

First checks, in this order

1. Reduce the operating temperature: improve cooling or lower the duty.

AL067: Encoder temperature warning

What it means: On ASDA-A2, A3 and B3 the encoder is between 85 °C and 100 °C, above the warning level but still within the protective range.^[2][3][4]

Drive response: WARN. A2: clear with DI.ARST. A3 and B3: servo stays on; clear by power cycle.

Likely causes

• Motor running hot from load or poor cooling
• High ambient temperature

First checks, in this order

1. Read the encoder temperature: P0-02 = 120 on A2, P0-02 = -124 on A3 and B3.
2. Improve cooling or reduce the load.
3. If the encoder runs more than 30 °C hotter than the motor, send the motor in.

AL068: Absolute data transmitted via I/O is in error (A2); Absolute data transmitted by I/O is in error (A3, B3)

What it means: Reading the absolute position through digital I/O went wrong: handshake order or timing error.^[2][3][4]

Drive response: WARN, servo stays on; clear by power cycle.

Likely causes

• DI.ABSQ and DO.ABSR handshake out of order
• Controller took more than 200 ms to answer after DO.ABSR turned on

First checks, in this order

1. Turn DI.ABSQ off only after DO.ABSR is off, and on only after DO.ABSR is on.
2. After DO.ABSR turns on, read DO.ABSD and switch DI.ABSQ on within 200 ms.

AL069: Wrong motor type

What it means: The absolute function is switched on but the motor has an incremental encoder.^[2][3][4]

Drive response: ALM, servo off; set P2-69 to 0, then power cycle.

Likely causes

• P2-69 set for absolute mode with an incremental motor fitted

First checks, in this order

1. Check whether the motor encoder is incremental or absolute.
2. Fit an absolute motor, or set P2-69 to 0 (P2-69.X = 0 on A3 and B3).

AL06A: The absolute coordinate has not been initialized (A2); Absolute position is lost (A3, B3)

What it means: The absolute origin has not been set, so the drive has no valid absolute position yet.^[2][3][4]

Drive response: WARN, servo stays on; clears once the absolute origin is set.

Likely causes

• Motor or drive used for the first time
• Battery ran flat and was replaced
• Loose or broken battery circuit
• On A3 and B3 also: E-gear ratio changed on a bus drive (CANopen, DMCNET, EtherCAT), damaged encoder cable, battery box J1 and J2 swapped, battery below 2.9 V

First checks, in this order

1. Check whether the absolute origin has been set.
2. Check the encoder cable and the battery box connection.
3. Set the absolute origin (homing).

AL070: Encoder does not complete the command which is issued by servo drive

What it means: The encoder did not finish a command from the drive, such as writing its barcode data. The A2 table lists it as WARN with the servo off.^[2][3][4]

Also on: ASDA-A3 and ASDA-B3 use AL070 for 'Encoder did not complete the read / write procedure', listed as a warning with the servo on, cleared by power cycle.

Drive response: WARN output, servo off; clear by power cycle.

Likely causes

• Encoder wiring wrong or loose

First checks, in this order

1. Check the encoder wiring and reconnect it firmly.

AL072: Encoder overspeed

What it means: The absolute encoder saw too high a speed: over 8,800 rpm when powered by the drive, over 10,000 rpm on battery power.^[2][3][4]

Drive response: ALM, servo off. A2: DI.ARST. A3 and B3: power cycle.

Likely causes

• Axis back-driven fast, for example a high-ratio gearbox turned by the mechanism
• Noise or poor grounding
• Low battery (listed by A3, B3)

First checks, in this order

1. Ground the motor and separate and shield the encoder cable.
2. Check the motor speed stays within its rating.
3. Measure the battery (below 3.1 V is low) and check its wiring.
4. Set the absolute origin again if position is lost.

AL073: Encoder memory error

What it means: The encoder hit an error reading or writing its own EEPROM.^[2][3][4]

Drive response: ALM, servo off. A2: DI.ARST. A3 and B3: power cycle.

Likely causes

• Noise or poor grounding
• Encoder fault

First checks, in this order

1. Ground the motor and separate and shield the encoder cable.
2. Check the motor speed stays within its rating.
3. If it stays, send the motor in.

AL074: Absolute encoder single turn position error (A2); Encoder single-turn absolute position is in error (A3, B3)

What it means: The single-turn position inside the absolute encoder is in error.^[2][3][4]

Drive response: ALM, servo off. A2: DI.ARST. A3 and B3: power cycle.

Likely causes

• Noise or poor grounding
• Encoder fault

First checks, in this order

1. Ground the motor and separate and shield the encoder cable.
2. Check the motor speed stays within its rating.
3. If it stays, send the motor in.

AL075: Absolute encoder position error (A2); Encoder absolute number of revolutions is in error (A3, B3)

What it means: The absolute encoder's position (turn count) is in error.^[2][3][4]

Drive response: ALM, servo off. A2: DI.ARST. A3 and B3: power cycle.

Likely causes

• Noise or poor grounding
• Encoder fault

First checks, in this order

1. Ground the motor and separate and shield the encoder cable.
2. Check the motor speed stays within its rating.
3. If it stays, send the motor in.

AL077: Encoder computing error (A2); Encoder internal error (A3, B3)

What it means: Internal computing error inside the encoder.^[2][3][4]

Drive response: ALM, servo off. A2: DI.ARST. A3 and B3: power cycle.

Likely causes

• Noise or poor grounding
• Encoder fault

First checks, in this order

1. Ground the motor and separate and shield the encoder cable.
2. Check the motor speed stays within its rating.
3. If it stays, send the motor in.

AL079: Encoder parameter error (A2); Encoder parameter setting incomplete (A3, B3)

What it means: A parameter was written to the encoder but the drive has not been power cycled, so the new value is not active.^[2][3][4]

Drive response: ALM, servo off; cycle power (the A2 clearing table also lists DI.ARST).

Likely causes

• Encoder parameter written without a following power cycle

First checks, in this order

1. Check whether an encoder parameter was just written.
2. Cycle power to activate it.

AL07A: Loss of encoder Z pulse (A2); Encoder Z phase position is lost (A3, B3)

What it means: The encoder's Z (index) pulse position is lost or wrong.^[2][3][4]

Drive response: ALM, servo off; A2: clear by power cycle.

Likely causes

• Noise or poor grounding
• Encoder fault

First checks, in this order

1. Ground the motor and separate and shield the encoder cable.
2. If it stays, send the motor to Delta or the distributor (A3 and B3 say to send it straight back).

AL07B: Encoder memory busy (A2); Encoder memory is busy (A3, B3)

What it means: The encoder's memory is busy and did not respond in time.^[2][3][4]

Drive response: ALM, servo off. A2: DI.ARST. A3 and B3: power cycle.

Likely causes

• Noise or poor grounding
• Encoder fault

First checks, in this order

1. Ground the motor and separate and shield the encoder cable.
2. Check the motor speed stays within its rating.
3. If it stays, send the motor in.

AL07C: Command to clear the absolute position is issued when the motor speed is over 200 rpm

What it means: A command to reset the absolute position arrived while the motor was turning faster than 200 rpm.^[2][3][4]

Drive response: WARN, servo stays on; repeat the position reset below 200 rpm (A3 and B3 also allow DI.ARST or power cycle).

Likely causes

• Absolute position reset sent while the axis was moving

First checks, in this order

1. Slow the motor below 200 rpm before resetting the absolute position.
2. Repeat the absolute position clearing procedure.

AL07D: Servo drive power is cycled before AL07C is cleared (A2); Motor stops operating when servo drive power is cycled before AL07C is cleared (A3, B3)

What it means: Power was cycled while AL07C was still active, so the motor stops.^[2][3][4]

Drive response: ALM, servo off; clear with DI.ARST, then handle AL07C.

Likely causes

• Drive switched off and on with AL07C uncleared

First checks, in this order

1. Clear this alarm with DI.ARST; AL07C then appears.
2. Clear AL07C by repeating the absolute position reset below 200 rpm.

AL07E: Encoder clearing procedure error (A2); Error occurs when the encoder clears the procedure (A3, B3)

What it means: The encoder clearing procedure retried more than the allowed number of times (11 in the A3 and B3 manuals).^[2][3][4]

Drive response: ALM, servo off; clear with DI.ARST (A3 and B3 also by power cycle).

Likely causes

• Poor communication quality with the encoder

First checks, in this order

1. Check encoder cable, grounding and shielding.
2. A3 and B3: watch the communication error count with P0-02 = -80; if it is normal, clear with DI.ARST.

AL083: Servo drive outputs excessive current

What it means: Drive output current went over the firmware limit, so the drive cut out to keep the IGBTs from burning.^[1][2][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Short circuit in the U, V, W cable (worn insulation or exposed wire)
• Wrong U, V, W order or a missing phase to the motor, often with non-Delta cables
• Analog signal ground tied to another ground, picking up noise

First checks, in this order

1. Inspect the motor power cable and connector; replace a damaged cable.
2. Check U, V, W order and that all three phases reach the motor.
3. Keep the analog signal GND separate from other grounds as shown in the wiring chapter.

AL085: Regeneration error (B2); Regeneration setting error (A2, A3, B3)

What it means: Regeneration control error: the regenerative resistor is not working but the bus voltage stays high (about 400 V) during braking.^[1][2][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Wrong regenerative resistor or external resistor not connected
• P1-53 not 0 with no resistor fitted
• P1-52 or P1-53 set wrong

First checks, in this order

1. Check the regenerative resistor wiring and recalculate its size.
2. Set P1-52 and P1-53 to match, or P1-53 to 0 if no resistor is used.
3. If it stays, send the drive in.

AL086: Regenerative resistor overload

What it means: On ASDA-B2, A3 and B3, too much braking energy is being dumped into the regenerative resistor, so the resistor is overloaded.^[1][3][4]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Resistor too small or external resistor not connected
• P1-52 or P1-53 set wrong
• Braking energy above the capacity set in P1-53
• Supply voltage too high or interference on the supply
• Drive hardware fault

First checks, in this order

1. Check the resistor wiring and set P1-52 and P1-53 to match it.
2. If the braking energy is above P1-53, fit a larger resistor or lengthen deceleration.
3. Measure the supply voltage and remove interference sources.
4. Measure the DC bus at the P3 terminal and compare with P0-02 = 14 (DC bus monitor); a mismatch points to a drive fault.

AL086: Input voltage is too high

What it means: On ASDA-A2, the drive sees energy coming in while it is not regenerating, from interference or a supply above its rating.^[2]

Drive response: ALM, servo off; clear with DI.ARST.

Likely causes

• Supply voltage above the rated range
• Interference feeding energy into the drive
• Drive hardware fault

First checks, in this order

1. Measure the supply voltage and compare it with the drive specification.
2. Remove the interference source, use the right supply or add a voltage regulator.
3. If the supply is in range and it stays, send the drive in.

AL095: The servo drive does not connect to external regenerative resistor (A2); Regenerative resistor is disconnected (A3)

What it means: P1-53 says a regenerative resistor is fitted, but the drive cannot find one. On A2 this applies to 220 V models of 5.5 kW and above.^[2][3]

Drive response: WARN, servo stays on; clear with DI.ARST.

Likely causes

• External regenerative resistor not wired or wired wrong
• P1-53 not 0 while no resistor is used

First checks, in this order

1. Connect the external regenerative resistor and check P1-53.
2. If no resistor is used, set P1-53 to 0.

AL099: DSP Firmware Upgrade (A2); DSP firmware error (A3, B3)

What it means: Firmware was updated but the parameter memory (EEPROM) has not been reset. The A2, A3 and B3 tables list it on the ALM output with the servo off.^[2][3][4]

Drive response: ALM, servo off; P2-08 = 30, then 28, then power cycle.

Likely causes

• DSP firmware upgraded without resetting parameters

First checks, in this order

1. Set P2-08 to 30, then to 28, then cycle power.
2. If it persists after that, contact Delta.

AL099: DSP Firmware Upgrade

What it means: On ASDA-B2, firmware was updated but the parameter memory has not been reset; the B2 table lists it as WARN with the servo on.^[1]

Drive response: WARN, servo stays on; P2-08 = 30, then 28, then power cycle.

Likely causes

• DSP firmware upgraded without resetting parameters

First checks, in this order

1. Check whether the firmware was just upgraded.
2. Set P2-08 to 30, then to 28, then cycle power.

AL500: STO function is enabled

What it means: The Safe Torque Off input is active, so the drive has removed motor torque.^[2][3][4]

Drive response: ALM, servo off; clear with DI.ARST, fault reset 0x6040, or P0-01 = 0.

Likely causes

• Safety circuit (door switch, safety relay, E-stop) opened the STO inputs
• STO not used but the STO connector is not bridged (A3: short-circuit plug in CN10)

First checks, in this order

1. Find out why the safety circuit opened and close it.
2. A3: if STO is not used, fit the short-circuit connector in CN10.

AL501: STO_A loss (signal loss or signal error) (A2); SF1 lost (signal loss or signal error) (A3, B3)

What it means: STO channel A (SF1) signal is missing, or channels A and B disagree for more than 1 second.^[2][3][4]

Drive response: ALM, servo off. A2: DI.ARST, 0x6040 fault reset or P0-01 = 0. A3 and B3: power cycle; if it stays, keep the machine safe and call the distributor.

Likely causes

• STO_A (SF1) wiring fault
• Safety device switching the two channels at different times

First checks, in this order

1. Check the STO_A (SF1) wiring.

AL502: STO_B loss (signal loss or signal error) (A2); SF2 lost (signal loss or signal error) (A3, B3)

What it means: STO channel B (SF2) signal is missing, or channels A and B disagree for more than 1 second.^[2][3][4]

Drive response: ALM, servo off. A2: DI.ARST, 0x6040 fault reset or P0-01 = 0. A3 and B3: power cycle; if it stays, keep the machine safe and call the distributor.

Likely causes

• STO_B (SF2) wiring fault
• Safety device switching the two channels at different times

First checks, in this order

1. Check the STO_B (SF2) wiring.

AL503: STO self-diagnostic error

What it means: The drive's STO circuit failed its own self test.^[2][3][4]

Drive response: ALM, servo off; contact the distributor.

Likely causes

• Fault in the drive's STO circuit

First checks, in this order

1. Contact the distributor; the drive needs service.

AL555: System Failure

What it means: DSP processing error inside the drive.^[1][2][3][4]

Drive response: Drive stops; send for repair.

Likely causes

• Internal drive fault

First checks, in this order

1. Do not change anything; send the drive to Delta or the distributor.

AL880: System Failure

What it means: DSP processing error inside the ASDA-B2 drive.^[1]

Drive response: Drive stops; send for repair.

Likely causes

• Internal drive fault

First checks, in this order

1. Do not change anything; send the drive to Delta or the distributor.

AL283: Forward Software Limit (A2); Software positive limit (A3, B3)

What it means: The position command went past the forward software limit (P5-08 on A2). The check uses the command, so the axis may stop just short of the limit.^[2][3][4]

Drive response: WARN, servo stays on; clears when the motor moves back (A2 also: NMT reset node or 0x6040 fault reset).

Likely causes

• Target position beyond the forward software limit
• Software limit set too tight for the job

First checks, in this order

1. Check the target position and the software limit P5-08.
2. Set a suitable deceleration time for the limit stop (P5-03).

AL285: Reverse Software Limit (A2); Software negative limit (A3, B3)

What it means: The position command went past the reverse software limit (P5-09 on A2). The check uses the command, so the axis may stop just short of the limit.^[2][3][4]

Drive response: WARN, servo stays on; clears when the motor moves back (A2 also: NMT reset node or 0x6040 fault reset).

Likely causes

• Target position beyond the reverse software limit
• Software limit set too tight for the job

First checks, in this order

1. Check the target position and the software limit P5-09.
2. Set a suitable deceleration time for the limit stop (P5-03).

AL235: PR command overflows (A2); Position counter overflow warning (A3, B3)

What it means: An absolute PR move was commanded after the feedback position counter (FB_PUU) overflowed or before the origin was set again, so the drive cannot place it correctly.^[2][3][4]

Drive response: WARN, servo stays on; clear by running homing.

Likely causes

• Axis kept running one way until the position counter overflowed
• P1-01.Z or the E-gear ratio (P1-44, P1-45) changed without homing again
• Homing started but not finished
• AL060 or AL062 occurred earlier

First checks, in this order

1. Scope the feedback position to see whether it overflowed.
2. Run the homing procedure.

AL35F: Emergency stop (during deceleration) (A2); Emergency stop during deceleration (A3, B3)

What it means: A digital input set to function 0x47 (emergency stop with deceleration) turned on and the motor is decelerating; when it reaches zero speed the drive shows AL3CF.^[2][3][4]

Drive response: WARN (A2 Mode C lists ALM), servo on while decelerating; clear by power cycle.

Likely causes

• Emergency stop input 0x47 triggered on purpose or by a wrong DI setting

First checks, in this order

1. Check which input is set to 0x47 (P2-10 to P2-17, P2-36 to P2-40) and why it switched on.

AL3CF: Emergency Stop

What it means: After AL35F the motor has stopped, and the drive holds the emergency stop with the servo off.^[2][3][4]

Drive response: WARN (A2 Mode C lists ALM), servo off; clear by power cycle.

Likely causes

• Emergency stop input 0x47 triggered on purpose or by a wrong DI setting

First checks, in this order

1. Check which input is set to 0x47 (P2-10 to P2-17, P2-36 to P2-40) and why it switched on.