ABB VFD Problem

We are having a ABB make VFD - ACS800 for fan application. It was commissioned and working for last three months. Now it is not responding to DCS input (4-20ma) and increse/decrese 24 V DC input from VFD panel for any increse/decrease command. Any change made from these two destinations leads to bringing the speed to ZERO with current indication in the existing value. However it is responding to HMI Keypad operation. No specific display in HMI screen.

Regards

R.Thiyagarajan

rthiy, I am very familiar with the ACS800 and will try to help you.

I am having a little trouble understanding your description of the problem. You mention a 4-20ma signal for speed and you also mention increase/decrease inputs on the 24VDC digital inputs.

Please check Group 99 Parameter 02 and advise what is entered there. That parameter (99.02) is where the Macro is entered which defines the configuration of all of the analog and digital input terminals.