Frequently asked questions

FA276076

25 November 2022

Issue:
What are some possible causes of SLF3 or HMI COM Fault on an ATV61 or ATV71 AC Drive.

Product Line:
ATV61 / ATV71 series drives

Environment:
Where the HMI keypad is being used to control the start/stop of the drive and/or the speed reference: All models, All serial numbers.

Cause:
Customer unable to find the answer in existing literature

Resolution:
HMI Com fault is caused when the HMI loses communication with the drive.   The HMI module of the ATV61/ATV71 series drives establishes a Modbus RTU connection at power up with the HMI being the Modbus Server.  This connection is separate from the Modbus/Canopen channel and is isolated.  This fault can only occur when the drive is configured to receive the start/stop control and/or the speed reference from the keypad.  

When this fault occurs, the most common causes are: 
- Someone accidently disconnected the cable from the drive or back of the HMI
- Enclosure Door was opened and connection to the back of the HMI Mount is loose or was disconnected.
- Check +10v to COM on the Control Terminals on the drive to ensure that nothing is pulling that down, particularly if the HMI remotely mounted more than 100ft from the drive.
- A failure of the HMI itself (part# VW3A1101)
- If the keypad is mounted remotely, the cable connecting it to the drive has failed. (VW3A1104RXX where XX = 10 for 1 meter cable, 30 for 3 meter, 50 for 5 meter or 100 for 10 meter)