Yaskawa A1000 Er-17 Fault - Causes & Fix

Yaskawa A1000 Er-17 Fault — What It Means

The Er-17 code (sometimes called Reverse Prohibited Error) appears when the Yaskawa A1000 drive attempts Inertia Auto-Tuning but cannot rotate the motor in reverse. Inertia Auto-Tuning requires the drive to briefly accelerate and decelerate the motor in both forward and reverse directions to calculate load inertia. When a parameter setting or external signal prevents reverse rotation, the tuning process fails and triggers Er-17.

This is a logic and configuration fault, not a hardware failure. The drive is functioning correctly but is blocked by application settings. Note that this fault code does not exist as AL-17 in Yaskawa documentation. AL codes typically refer to alarms, whereas Er-17 is a specific error related to tuning restrictions.

Before You Replace Anything

Some users confuse Er-17 with encoder feedback faults and replace option cards or cables. Er-17 is exclusively a rotation direction logic error. Check parameter b1-04 and external inhibit signals before replacing any hardware.

Jump to Fix

Common Causes

• Parameter b1-04 set to Restrict Reverse (~70%) The Motor Operation Direction parameter is configured to forward-only mode, blocking the tuning process from testing reverse rotation.
• External reverse-inhibit signal active (~15%) A PLC, switch, or control board is sending a reverse lockout signal to the drive input terminals during the tuning attempt.
• Application mechanically cannot reverse (~10%) The machine uses a unidirectional clutch, safety interlock, or other hardware that physically prevents reverse rotation, making the tuning attempt invalid.
• Tuning initiated in wrong control mode (~5%) The drive is in a control mode that does not support bidirectional auto-tuning, or the tuning sequence was started with reverse already disabled in logic.

Quick Diagnosis

Answer these to narrow it down fast.

Step-by-Step Fix

1. Access the drive parameter menu using the keypad or DriveWizard Plus software and navigate to parameter b1-04 (Motor Operation Direction).
2. Check the current value of b1-04. If it reads 1 (Restrict Reverse), the drive is blocking reverse rotation. If it reads 0, proceed to step 4.
3. Change b1-04 to 0 (Allow Forward and Reverse) only if the motor and mechanical load can safely rotate in reverse. Save the parameter change.
4. Inspect external control wiring at the drive input terminals. Use a multimeter to check for active reverse-inhibit signals from the PLC or control board during the tuning sequence.
5. Clear any active inhibit signals by disconnecting the control wire (if safe) or overriding the PLC logic. Confirm no voltage is present on the inhibit input.
6. Initiate Inertia Auto-Tuning again from the drive menu. Observe the motor for bidirectional movement and verify the error does not reappear.
7. If reverse is mechanically impossible, skip auto-tuning entirely. Manually enter the load inertia value in parameter b1-01 using motor and load specifications from your engineering documentation.

Parts Often Needed

When to Call a Pro

Call a qualified controls technician or application engineer if you cannot access the parameter menu due to password locks, if the mechanical system requires a detailed inertia calculation that exceeds your engineering knowledge, or if the drive is integrated into a complex PLC network where changing parameters or signals could affect other machinery. Also call a pro if you suspect the drive firmware or option card has a deeper configuration issue that parameter b1-04 alone does not resolve. For straightforward parameter changes and signal checks, most facility maintenance staff can handle Er-17 without outside help.

Rough cost: DIY runs about $0, 5-15 min. A pro service call runs about $100-200 for parameter programming visit.

See Also

• Yaskawa GA800 E26 Fault Code - Causes & Fix
• Yaskawa GA800 E37 Fault - Causes & Fix
• Yaskawa GA800 LF Fault - Causes & Fix
• Yaskawa GA800 E20 Fault Code - Causes & Fix