Yaskawa A1000 oFA32 — What It Means
The oFA32 fault on a Yaskawa A1000 VFD indicates a Communication Option Card Connection Error at the CN5-A port. The drive’s control logic has detected that the option card installed in that slot (for example a DeviceNet, Ethernet, or Modbus communication adapter) is missing, damaged, or non-functional. It can also mean the control board port itself is defective.
This is a digital handshake failure, not a simple loose wire. The drive expects to see a valid option card and cannot communicate with it. The fault will persist until the card or control board is repaired or replaced.
Before You Replace Anything
Technicians sometimes replace the entire control board when only the communication option card has failed. Always test with a known good option card of the same type before condemning the control board.
Common Causes
- Damaged option card (~50%) The communication adapter installed in CN5-A has burnt components, loose traces, or internal failures that prevent the drive from detecting it.
- Loose or improper installation (~25%) The option card is not fully seated in the slot or the locking mechanism is not engaged, breaking the electrical connection.
- Control board hardware failure (~15%) A fault in the control card’s CN5-A port or internal circuitry prevents communication with an otherwise good option card.
- Power supply issues (~10%) Intermittent power to the drive or option card causes false detection of the connection error.
Quick Diagnosis
Answer these to narrow it down fast.
Did the fault clear after reseating the option card and power cycling the drive?
No: Proceed to test with a known good option card of the same type.
Does a known good option card of the same type clear the oFA32 fault?
No: The control board CN5-A port is damaged. Replace the control board or drive.
Is the charge indicator LED off and DC bus below 50 Vdc before you work inside?
No: Wait at least 5 minutes after power-off and verify the charge LED is out before opening the drive.
Step-by-Step Fix
- Turn off all power to the drive at the main disconnect and wait for the charge indicator LED to extinguish, confirming the DC bus is below 50 Vdc (typically 5 minutes or more).
- Remove the option card from the CN5-A slot and inspect both the card edge connector and the slot for debris, corrosion, or bent pins.
- Reinstall the card by seating it firmly into the CN5-A slot and engaging the locking mechanism completely.
- Power the drive back on and check whether the oFA32 fault has cleared.
- Swap in a known good option card of the same type if the fault persists, to isolate whether the original card or the control board is at fault.
- Replace the control board if a known good option card still triggers oFA32, indicating the CN5-A port is damaged.
- Verify normal operation by monitoring the drive for stable communication with the option card and no recurrence of the fault.
Parts Often Needed
| Part | Notes |
|---|---|
| Yaskawa Communication Option Card (DN2, EM2, EN2, or model-specific) | Amazon | Match the exact card type originally installed in CN5-A. |
| Yaskawa A1000 Control Board | Amazon | Only needed if a known good option card still triggers the fault. |
When to Call a Pro
Call a qualified VFD technician or industrial electrician for this repair. The A1000 drive operates at high DC bus voltages (approximately 145% of line-to-line input voltage, around 650 Vdc for a 400 V line). Working inside the drive requires lockout-tagout procedures, verification that the DC bus is below 50 Vdc, and familiarity with communication option cards and control board replacement. Incorrect handling can result in electric shock or damage to the drive and connected equipment.
Rough cost: A pro service call runs about $200-800 depending on whether the option card or control board needs replacement.