Mitsubishi FR-A800 Error Code E.6

Mitsubishi PLC & VFD Critical System

Model: FR-A800 | Code: E.6

Applicable Systems
MELSEC FX3U MELSEC FX5U FR-A800 FR-A700 MR-J4 iQ-R Motion Controller (R32MTCPU/R16MTCPU)

Symptoms

The drive trips and the panel displays E.6, indicating a CPU error. The internal microprocessor has detected an internal fault or has been disrupted by external interference. The drive cannot continue operation.

Possible Causes

  • Strong electromagnetic interference (EMI) from nearby large equipment (welders, large contactors)
  • Internal integrated circuit (e.g., 1302H02) or optocoupler hardware failure
  • Power supply instability causing CPU reset or malfunction
  • Corrupted firmware or parameter data in the EEPROM

Troubleshooting Steps

  1. Step 1: Check the drive grounding connection
    Ground wire should be properly connected to the ground busbar with low impedance
  2. Step 2: Inspect for nearby sources of electromagnetic interference
    Move the drive or install EMI shielding if large EMI sources (welders, transformers) are nearby
  3. Step 3: Power off the drive completely, wait 30 seconds, and power back on
    If the fault clears and does not recur, it was likely caused by transient EMI
  4. Step 4: If the fault persists after power cycling, the internal CPU board or components are likely damaged
    Drive needs factory repair or board replacement

How to Reset

To reset: 1) Power off the drive completely (disconnect input power). 2) Wait 30 seconds. 3) Reapply power. 4) If E.6 clears, address the EMI source. 5) If E.6 persists, the drive needs repair. Caution: E.6 is a critical internal fault; do not attempt to reset repeatedly.

Frequently Asked Questions

  • Q: What is the difference between E.6 and E.7?

    E.6 indicates a CPU fault on the main control board. E.7 indicates a CPU fault on a different internal board or communication error between boards. Both are critical hardware faults requiring professional repair.

  • Q: Can EMI really cause E.6?

    Yes. Industrial environments with welding machines, large motor starters, or high-frequency equipment can generate EMI strong enough to disrupt the drive's CPU. Proper grounding, shielded cables, and EMI filters are essential.

Related Mitsubishi Fault Codes

Source: Mitsubishi FR-A800 Instruction Manual (Functions), 2024

Category: PLC & VFD