These rectifiers from the likes of Delta, Huawei etc are designed to work in a system built up of building blocks according to the end application, which will typically be telecomms, base station, solar power etc. It looks as if these particular ones use either RS485 or CAN to talk to the main system controller. The messaging is most likely proprietary so you'll probably have to buy the matching PSC to be able to go in and change stuff.
Note that these rectifiers are not very adjustable (42-58V?), as they are intended to work with a bank of stand by batteries - the name "rectifier" historically means that - sounds as if you are using them in such a system? These things plug into a rack system via the connectors on the back and are usually "hot pluggable" so you don't need to power the system off to change them. They should simply come on when you power them up but may need to see a battery voltage first, depending how it's been configured.
Have you tried to find a Delta "power system controller" (PSC)? It has a built-in web server so you can log into it with an Ethernet cable to change the configs. Look on Aliexpress or Alibaba if there's nothing nearer home. There's a quick overview here, that gives you an idea what is involved:
http://www.rectifier.co.za/Delta/psc-3-tds.pdf