Browse FAQs

What would cause a 4-20mA Loss Warning on an Altivar Process Drive?

Published date: 03 June 2019

What would cause a 4-20mA Loss Warning on an Altivar Process Drive?
How do I turn off the Red Flashing Warning Light?

Product Line:
Altivar Process Drive (ATV630, ATV930, ATV650, ATV950, ATV660, ATV960, ATV680, ATV980)

All serial numbers for Altivar Process Drive

Drive is displaying Warning or Error Codes:
AP1 - AI1 4-20 Loss Warning
AP2 - AI2 4-20 Loss Warning
AP3 - AI3 4-20 Loss Warning
AP4 - AI4 4-20 Loss Warning
AP5 - AI5 4-20 Loss Warning
LFF1 - AI1 4-20mA loss
LFF2 - AI2 4-20mA loss
LFF3 - AI3 4-20mA loss
LFF4 - AI4 4-20mA loss
LFF5 - AI5 4-20mA loss

The 4-20mA loss operates with 2 hysteresis: one threshold to activate the 4-20mA loss and the other threshold to allow the reset of this 4-20mA.
- When the AI value goes under 2mA the drive detects the 4-20mA loss.
- When the AI value goes over 3mA the drive allows the reset of 4-20mA loss
- When the AI value drops down pretty close to 2mA the drive displays a 4-20mA Loss Warning

Possible Remedies:
- Verify the connection on the analog inputs
- Check mA signal for possible interference
- This detected error can be cleared with the [Auto Fault Reset] Atr or manually with the [Fault Reset Assign] rSF parameter after the cause has disappeared

To Clear 4-20mA Loss if getting Warning Light
If getting a red warning light flashing on the keypad normally it is because it detects an AI2 or AI3 4-20mA Loss Warning. To clear the warning light try the following:
  • First, disable the 4-20mA warning
    • [Complete settings] [Error/Warning handling] [4-20mA loss]-> set to 'ignore'
  • Second, change unused analog inputs from Current to Voltage
    • [Complete settings] [Input/Output] [AI/AQ] [AI2 configuration]
    • [Complete settings] [Input/Output] [AI/AQ] [AI3 configuration]

Was this helpful?

What can we do to improve the information ?

Can't find what you are looking for?

Reach out to our customer care team to receive information on technical support, assistance for complaints and more.