Delta’s ASDA-A2 and ASDA-A3 servo drives share one alarm numbering scheme — AL.001 means overcurrent on both — but the hardware behind the numbers differs. The A2 spans 0.1–15 kW at 220 V or 380 V with a 20-bit encoder; the A3 covers 0.1–3 kW at 220 V with a 24-bit absolute encoder, 3.1 kHz bandwidth and a shared DC bus. This guide flags the differences where they matter, and every alarm name, trigger and clearing method follows Delta’s official ASDA-A2 / ASDA-A3 documentation, not third-party code lists.
The drive display shows the code as AL.xxx, and the panel LED tells you how serious it is: ALM means a trip, WARN a warning-class code (AL.023 early overload, AL.067 motor temperature warning, or AL.022 phase loss, a warning by default on the A3). Most trips clear with the DI.ARST digital input; encoder and EEPROM codes need a power cycle; AL.013 clears once DI.EMGS is released. If a code returns immediately, stop resetting and start measuring.
Fault manifestation: the drive trips at Servo On or during acceleration; output current has exceeded 1.5 times the maximum instantaneous rating.
Root causes: a shorted motor winding or frame fault, incorrect U/V/W wiring, a failed IGBT, or an aggressive command step.
Repair steps: disconnect the motor cables first. With a 500 V insulation tester, check each motor phase to frame: a healthy winding reads in the hundreds of megohms; anything near or below 1 MΩ points at the motor or its cable. Verify the U/V/W/GND order against the manual, then command the drive with the motor still disconnected: if AL.001 persists with no motor attached, the output module is suspect. Only then, soften the command profile.
Fault manifestation: AL.002 trips when the main-circuit voltage exceeds the rated value; AL.003 trips when the bus sags below the undervoltage level — on the A3 this is the DC bus falling below the P4.024 setting multiplied by √2.
Root causes: for AL.002, an over-high supply, the wrong power system (380 V into a 220 V drive), or regenerative energy with nowhere to go; for AL.003, a weak supply, a loose input terminal, a blown fuse, or several shared-DC-bus A3 axes decelerating simultaneously.
Repair steps: measure L1/L2/L3 under load and compare with the nameplate. The DC bus should sit near √2 × line voltage — about 310 V DC on a 220 V class drive, 540 V DC on a 380 V class unit. Retorque the input terminals; on multi-axis A3 cabinets, stagger the decel ramps first.
Fault manifestation: the trip appears during fast deceleration of a vertical or high-inertia axis; on the A3, AL.010 reports a voltage error during regeneration.
Root causes: the regenerative resistor is not connected, its resistance does not match the application, the decel time is too short, or its thermal protection has opened.
Repair steps: power down and measure the resistor element — an open or scorched resistor is the most common find. Check the P+/PR wiring, lengthen the decel time, and only then consider a larger resistor or an active regen unit.
Fault manifestation: AL.006 trips when the motor and drive stay overloaded beyond the I²t curve; AL.023 is the pre-warning.
Root causes: mechanical binding, a brake that is not fully releasing, an undersized motor, hunting from poor tuning, or an overheated cabinet.
Repair steps: check the motor surface temperature, confirm the brake actually releases, rotate the mechanism by hand with the motor decoupled, and compare running current with rated current.
Fault manifestation: the slot means two different things depending on generation. On the A3, AL.007 is an excessive deviation of the speed command — commanded versus feedback speed beyond the P2.034 window; on the A2 it is plain over-speed beyond the same threshold. AL.009 trips on both when position error exceeds P2.035. (AL.008 is the cousin: pulse input frequency above the hardware limit.)
Root causes: a slipping coupling or loose keyway, gearbox backlash, a noisy encoder cable, gains too low for the load inertia, or P2.035 set tighter than the mechanics can follow. An A2 over-speed usually traces to a noisy analog command or P2.034 set too low.
Repair steps: mark the coupling and confirm it does not slip under torque, check encoder lines for noise, and re-run auto-tuning with the real inertia ratio. Raise P2.035 only if the mechanics justify it — masking a jam with a wide window destroys parts quietly.
Fault manifestation: AL.011 (encoder error, abnormal pulses) usually clears after a power cycle; AL.024 initial magnetic field error, AL.025 internal memory/counter error, AL.026 unreliable internal data (three consecutive failures), AL.027 reset error, AL.028 battery voltage or encoder internal error, AL.029 gray code error, AL.034 internal communication error and AL.036 alarm status error form the deeper family. The A2 reports AL.035 as motor over-temperature above 105 °C (AL.067 is the 85 °C warning), while the A3 uses the same slot for encoder or external sensor temperature above 100 °C.
Root causes and repair: damaged encoder cable (especially in drag chains), poor shield grounding, a dead battery, or genuine encoder failure. Reseat CN2 at both ends, inspect the cable for the classic flexing-fatigue break near the connector, and keep encoder wiring away from power wiring. Swap in a known-good cable before condemning the motor — the cable is guilty far more often than the encoder.
Fault manifestation: after first power-up the A3 shows AL.06A because the absolute coordinate system has never been established; AL.060 appears when a good coordinate system was lost — typically from a battery below roughly 2.8–2.9 V, a battery-circuit contact loss, or a battery swapped with control power off.
Root causes: an expired battery, a damaged encoder cable feeding the battery circuit, or the battery pack J1/J2 leads reversed so the buffer capacitor never charges.
Repair steps: replace the battery with the drive powered so the encoder never loses supply, verify J1 goes to the battery and J2 to the drive, then rebuild the absolute origin with the P2.070 procedure and home the axis. AL.062 (revolution overflow beyond ±32,768 turns) and AL.289 (PUU overflow) are handled the same way — a wrong battery swap is exactly what creates this alarm.
Fault manifestation: AL.016 reports abnormal IGBT temperature; AL.030 fires when collision torque reaches the P1.057 level for longer than the P1.058 time; AL.031 signals a U/V/W/GND power wiring error. The A3 adds AL.032 (encoder vibration) and AL.033 (26-pin converter-box connector disconnected).
Repair steps: for AL.016, clean the heatsink, check the fan, verify ambient temperature, and confirm the temperature monitor returns to a normal band. For AL.030, inspect the mechanism for an actual crash first; adjust P1.057/P1.058 only if the protection was mis-tuned. For AL.031, power down and verify every conductor and the ground before re-energising.
Fault manifestation and repair: AL.017 (EEPROM error) means a parameter write failed — a parameter reset is mandatory, then re-servo; if it happens mid-operation, DI.ARST clears it. AL.045 appears at power-up when the E-gear ratio (P1.044 / P1.045) falls outside its valid range — 1/50 to 25,600 on the A2, up to 262,144 on the A3. AL.042 reports the analog speed command exceeding the level set in P1.083, and AL.044 warns that too many motor-control functions are enabled at once. AL.099 is not a fault: after a DSP firmware upgrade, set P2.008 to 30, then 28, and cycle power. Always back up the full parameter file before any reset.
Every six months: blow out cabinet dust, check fans, retorque power terminals, and inspect CN1/CN2 latches. Annually: insulation-test the motor with the drive disconnected, verify regenerative resistor health, and check DC-bus ripple on drives past mid-life. For absolute systems, replace the encoder battery every two to three years before it drops below 2.8 V, always with control power on, and keep a recent parameter backup. Most AL.006 and AL.016 tickets trace back to heat, not electronics.
Can an ASDA-A3 drive run an ASDA-A2 motor? Yes — the A3 supports both A2 (ECMA) and A3 (ECM-A3) motors, but the motor type and encoder parameters must be configured correctly, and absolute-system behaviour differs between encoder generations.
AL.011 clears after a power cycle but returns hours later? That pattern means an intermittent connection, not a dead encoder — replace the cable first.
Is AL.023 dangerous? Not yet — it precedes AL.006. Fix the mechanical cause while you still have production time.
When a trip turns out to be hardware — a shorted module, a cooked resistor, a drive past economic repair — replace rather than diagnose. Test Well stocks the servo drives and amplifiers category for cross-brand upgrades, the full Delta AC drive range including the Delta VFD007M43B VFD-M drive shown above, and IGBT and IPM power modules for board-level repairs. Every unit ships tested with manuals and technical support.
