Our customer has AC450 (PM511) controlling ACS600. What is needed if drive is changed to ACS880?
I would need to RTFM to answer in detail.
Assuming that the drive is directly controlled from the AC450 and this isnt a sectional drive with AC70 or AC800M controllers, then the basic principle is you need a new MMCX element for the drive and you need to change the PC program element for the Drive. Check the DB and PC element manuals for details of the various changes required.
only for the drive: depending on the type of HW control that you have actually between the drive and the control unit, you need to select the equivalent solution for the ACS880 unit. FDCO-01 is one possible solution, I agree with Rob that you need to reconfigure your AC450