What the code is
The ACS800-U1-0120-5+P901+V944 is an ABB drive carrying the +P901 and +V944 suffixes on the base order code ACS800-U1-0120-5.
Cross-platform read against the newer and older siblings
Listed masses: ACS880-01-156A-5 at 55.00 kgs, ACS550-U1-157A-4 at 89.81 kgs, ACS580-01-180A-4 at 54.43 kgs. The ACS880-01-156A-5 is the closest same-function ABB platform; re-validate frame current, bus topology, and I/O mapping before treating it as a mechanical drop-in. ACS550-U1-157A-4 at 89.81 kgs is the legacy predecessor; ACS580-01-180A-4 at 54.43 kgs is the modern general-purpose platform. None share the +P901 / +V944 option coding, so re-validate the option-suffix meaning on the replacement order key.