Yaskawa A1000 AL-18 Fault — What It Means
The fault code AL-18 is not documented in official Yaskawa A1000 VFD fault code lists. The closest matching fault is oPE18 (Online Tuning Parameter Setting Error). This code indicates the drive has detected a function setting that cannot be used with the currently selected motor control method. For example, enabling a feature valid only for vector control while the drive is configured for V/f mode, or setting incompatible PID or encoder parameters.
Because AL-18 is not an official Yaskawa code, verify the exact fault displayed on your drive’s keypad or software. If you see oPE18, the cause is almost always a parameter configuration conflict rather than hardware failure. Check your motor control method selection and review all related function parameters against the manual’s compatibility tables.
Before You Replace Anything
Technicians sometimes replace the control board when seeing parameter errors, but oPE18 is nearly always a settings conflict. Review parameter N1-01 and all H3, L6, and E1/E5 settings against the control-method compatibility table before ordering any hardware.
Common Causes
- Wrong motor control method for enabled functions (~40%) A feature such as auto-tuning, PID control, or encoder feedback is enabled but the motor control method in N1-01 does not support that function.
- Conflicting PID parameter selections (~25%) Both H3-02 and H3-06 (or H3-10) PID feedback sources are enabled simultaneously, which the drive does not allow.
- Incorrect motor data parameters (~20%) Values in E1-04, E1-06, E1-07, E1-09, or E1-11 (motor 1) or corresponding motor 2 parameters are out of range or inconsistent with the control method.
- Encoder or PG settings mismatch (~10%) L6-02 or L6-03 encoder parameters are configured for a mode that requires a pulse generator, but the control method does not use one (or vice versa).
- Control board CPU or memory fault (~5%) Physical damage to the control board causes persistent parameter errors even after correct settings are entered (rare for oPE18).
Quick Diagnosis
Answer these to narrow it down fast.
Does the keypad display exactly AL-18, or does it show oPE18?
No: Note the exact code displayed and cross-reference it in the A1000 fault code table before troubleshooting.
Is parameter N1-01 set to Sensorless Vector (1) or Closed-loop Vector (2), and are PID or encoder parameters active?
No: Check E1-xx motor data parameters for valid ranges and consistency with the selected motor control method.
Does the fault clear after correcting parameters and power-cycling the drive (off for 5 minutes)?
No: Contact Yaskawa support or a qualified VFD technician for control board diagnostics or drive replacement.
Step-by-Step Fix
- Verify the exact fault code displayed on the drive keypad or via software. AL-18 is not documented in Yaskawa A1000 manuals; the closest match is oPE18 (Online Tuning Parameter Setting Error).
- Record all current parameter settings before making changes. Use the keypad or drive software to note N1-01, all H3-xx, L6-xx, E1-xx, and E5-xx values.
- Check parameter N1-01 (Motor Control Method). Write down the current value: 0 = V/f, 1 = Sensorless Vector, 2 = Closed-loop Vector, 3 = V/f with PG.
- Review function compatibility in the Yaskawa A1000 manual. Compare the control method in N1-01 with the functions enabled in H3 (PID), L6 (encoder), and E1/E5 (motor data). Disable or correct any parameter that is not valid for your motor control method.
- Correct motor data parameters in E1-04, E1-06, E1-07, E1-09, and E1-11 (motor 1) and corresponding E2-xx or E5-xx for motor 2 or sensorless/closed-loop modes. make sure values match your motor nameplate and control method requirements.
- Power-cycle the drive by turning off the main disconnect, waiting at least 5 minutes for capacitors to discharge, then restarting. Observe whether the fault clears.
- If the fault persists after parameter corrections and power cycling, contact Yaskawa technical support or a qualified VFD service center. The control board may need diagnostics or replacement if hardware damage is present.
Parts Often Needed
| Part | Notes |
|---|---|
| Yaskawa A1000 control board | Amazon | Part number varies by drive frame size; consult Yaskawa parts catalog or your drive nameplate. |
| Yaskawa A1000 VFD (complete unit) | Amazon | For cases where control board replacement is not feasible or multiple sections are damaged. |
When to Call a Pro
Call a qualified VFD technician or contact Yaskawa support if you are unfamiliar with parameter programming, if the exact fault code does not match oPE18, or if the fault persists after you have corrected all parameter conflicts and power-cycled the drive. VFD parameter errors can indicate control board hardware damage if settings cannot be saved or if the drive displays CPU-related faults (such as CPF18). A technician will use Yaskawa’s diagnostic software to verify control board health and determine whether board replacement or a complete drive swap is necessary. Do not attempt control board replacement yourself unless you are trained in high-voltage DC bus safety and ESD precautions.
Rough cost: A pro service call runs about $150-400 for parameter review and correction; $800-2500 if control board truly failed.