Yaskawa A1000 oFA15 — What It Means
The oFA15 code (often misread as AL-15) means the A1000 drive has lost communication with an installed option card. This includes PG encoder cards, PID cards, or communication modules. The drive detects the slot is occupied but cannot establish an electrical connection, so it halts operation to protect the system. The fault typically appears after a mechanical vibration event, a wiring change, or random intermittent contact degradation over time.
Unlike a software parameter error, oFA15 is a hardware connectivity problem. The option card must make solid electrical contact with the control board and the card must receive clean signals from any attached encoder or external device. If the card is loose, the cable is broken, or shield grounding is poor, noise or open circuits will trigger the fault.
Before You Replace Anything
Technicians often replace the option card when the real problem is a broken encoder cable or loose termination at the peckerhead terminal block. Always perform continuity testing on the cable before ordering a new card.
Common Causes
- Loose or unplugged option card (~40%) The option card is not fully seated in the slot or has vibrated loose over time, breaking electrical contact with the control board.
- Broken or damaged encoder cable (~30%) The cable connecting the encoder to the option card has internal wire breaks, melted insulation, or loose terminations that interrupt the signal path.
- Faulty terminations at the peckerhead (~15%) Wire connections at the device terminal block are loose, corroded, or have conductors folded back and hidden behind the terminal strip.
- Improper grounding of shielded lines (~10%) The encoder cable shield is not grounded or is grounded at both ends, allowing noise to disrupt the low-voltage encoder signal and confuse the option card.
- Damaged option card or control board (~5%) The option card itself has internal component failure or the control board slot on the drive is defective, preventing communication even when all wiring is intact.
Quick Diagnosis
Answer these to narrow it down fast.
Does the fault clear after you reseat the option card and power cycle the drive?
No: Move to cable continuity testing and termination inspection.
Does the encoder cable show continuity (near 0 Ω) between the option card plug and the encoder device?
No: The cable is broken internally or has a bad termination. Replace the shielded encoder cable.
Does the fault persist after swapping in a known-good option card?
No: The original option card was faulty. Keep the new card installed.
Step-by-Step Fix
- Power down and isolate the drive from mains power and wait for all indicator lights to go dark before opening any covers.
- Remove the option card by releasing the retention screws or clips and pulling it straight out of the slot.
- Inspect the slot and card edge connector for debris, bent pins, or corrosion, and clean with contact cleaner if needed.
- Reseat the card firmly so the edge connector makes full contact with the slot, and tighten the retention hardware.
- Check encoder cable terminations at both the option card plug and the device terminal block, looking for loose screws, melted insulation, or folded-back wires.
- Test cable continuity with a multimeter from the option card plug to the encoder device, expecting near 0 Ω on each conductor.
- Verify shield grounding by measuring resistance from the cable shield to ground, expecting less than 1 Ω at one end only, not both.
- Swap the option card if the fault persists after reseating and cable checks, using a known-good PGX2, PGB2, or PGF2 card as appropriate for your encoder type.
- Replace the control board if a new option card still triggers oFA15, because the drive slot is likely defective.
Parts Often Needed
| Part | Notes |
|---|---|
| PG Encoder Option Card (PGX2, PGB2, or PGF2) | Amazon | Match the card type to your encoder voltage and protocol, typically PGX2 for standard incremental encoders. |
| Shielded Encoder Cable | Amazon | Replace if continuity testing fails or insulation is damaged, maintaining the same wire gauge and shield type as the original. |
| A1000 Control Board | Amazon | Required if the option card slot is damaged, consult your drive model number for the correct board part number. |
When to Call a Pro
Call a qualified electrician or VFD technician if you are uncomfortable working inside live or recently powered industrial equipment, if the fault persists after reseating the card and checking terminations, or if you lack a multimeter and experience to test cable continuity. Professionals have known-good spare cards for swap testing and can quickly isolate whether the problem is the card, the cable, or the drive control board. If the encoder is not required for your application, a technician can reconfigure the drive parameters to run open-loop as a temporary workaround while parts are ordered.
Rough cost: A pro service call runs about $200-500.