Thanks for the replies.
We actually have one machine that uses ABB DCS400 drives, one for the wind and the other for the unwind. They use ABB winding software. These drives have been running for approximately 10 years without a single hiccup.
I want to keep the price down, and if possible, forego the extra expense of winding software. I inquired about ABB winding software a few months ago and the sales rep said that you actually had to talk to ABB before they would sell it - apparently they won't sell it to just anybody. The DCS800 looks like it has some pretty flexible programming capabilies and if the documentation is good enough, I'm confident that I can come up wth a tension regulation scheme that will be sufficient for our needs.
Also, I'm not married to the idea of using only ABB products.