I'm thinink the Vicon is a soft-core baler?
The most favored is a rubber belt baler. Newer ones with wider belts, good tension, open throat.
Next are NH bar & chain balers. Work about as good, but wear a little faster & will knock leaves off alfalfa. Do better in cornstalks & the rough stuff tho.
Then are the soft-core balers, or fixed-chamber. They usually have big metal drums around the bale, & throw hay into the middle, keep tumbling it around. Only as the bale gets full do they start to pack the hay tight. Some say they allow you to bale damper hay, as the softer center will dry out. Others note that the bales just don't pack as tight, and settle & mold more if stored outside.
The very old round balers were closed-throat. The hay had to pass through 2 rollers real close together. Caused a lot of plugging & could not handle damp hay at all.
A monitor usually works off 12v, and it has a spring roller on the 2 outer belts. if one belt gets looser, the monitor will show a light to move over in that direction. Keeps you from having to twist around & guess yourself which side to fill. End up making better bales, tighter. The newer monitors may also have size, twine, & tightness adjustments on it, and basically run & control the whole baler.
Round baler needs at least 1 hyd set to open & close the baler. Some models use a rope you pull to move the twine, some use a 2nd hyd set, and some (newer) use 12v electric to move the twine.
Pretty much all there is. Newer balers feed better, make tighter bales, have better monitors that help you keep baling looking forward. Older ones waste fine short hay, don't start a bale as easily, have no monitors. Kinda sorta how it sorts out.
--->Paul