Schneider ATV320 Fault Code LFF3

Schneider Electrical Warning Signal

Model: ATV320 | Code: LFF3

Applicable Systems
ATV320 ATV340 ATV630 ATV930

Symptoms

The analog input AI3 configured for 4-20mA has detected a signal loss. The current on AI3 and COM has fallen below 4mA, indicating a broken wire or failed sensor.

Possible Causes

  • 4-20mA signal wire on AI3 is disconnected or broken
  • Sensor or transmitter providing the 4-20mA signal has failed
  • AI3 is configured for 4-20mA but no signal source is connected
  • Signal loop resistance is too high causing voltage drop

Troubleshooting Steps

  1. Step 1: Check the AI3 wiring and ensure the 4-20mA signal source is connected
    AI3 wiring is intact and signal source is operational
  2. Step 2: Verify the AI3 parameter configuration matches the signal type (0-5V vs 4-20mA)
    AI3 is correctly configured for the actual signal type
  3. Step 3: If AI3 is not needed, deactivate the alarm by setting the alarm group parameter (A1C/A2C/A3C) to 'unassigned'
    Alarm is deactivated and drive operates normally
  4. Step 4: If the alarm is needed, check the sensor/transmitter for proper operation
    Sensor provides a stable 4-20mA output

How to Reset

To reset: 1) Restore the 4-20mA signal on AI3. 2) Press STOP/RESET. 3) Restart. Alternatively, deactivate AI3 alarm if not needed: CONF->FULL->I/O, set A3C to 'unassigned'.

Frequently Asked Questions

  • Q: How do I clear LFF3 on ATV320?

    Check AI3 wiring and signal source. If AI3 is not needed, go to CONF->FULL->I/O and set A3C (alarm group 3) to unassigned. If needed, fix the 4-20mA signal.

Related Schneider Fault Codes

Source: Schneider Electric FAQ FA313354; Schneider ATV320 Programming Manual

Category: Electrical