Cause : ACI loss comes when analog input loss (including all the 4–20 mA analog signal) due to ACI cable is loose or cut off, external device failure or hardware issue in drive control card.

An ACI loss error on your Delta MS300 drive indicates a problem with the Analog Current Input (ACI) signal. The ACI is an external analog signal, typically a voltage or current within a specific range (usually 4-20mA), used to control the speed or another parameter of the motor connected to the drive.

1. Tighten the terminal.
2. Replace the cable with a new one.
3. Replace the device with a new one.
4. Check all the wiring.