Cause : Diagnostics CPLD error comes when diagnostics in CPLD have detected an error. The CPLD is a programmable chip on the control board of the drive. It's responsible for handling specific tasks and logic functions essential for the drive's operation.

"INFR" Internal error 27 fault in Schneider ATV950 drive indicate "Diagnostics CPLD" error. This means an issue within the core functionality of your device. CPLDs are like tiny, customizable computers that handle critical tasks within electronic devices.