Forum won't let me edit my previous post, so whatever. Here's a somewhat more verbose explanation, for posterity.
I encountered this post while researching a similar problem to OP. I think I've found a solution, and documented it below:
The above linked page didn't have the right software, but I was able to obtain Motion Dialogue by emailing Kollmorgen directly and asking nicely. For the love of god don't buy a sketchy CD-ROM from the internet. The executable file will not run on a 64-bit architecture. In fact, a modern computer will quite strongly believe that the binary file that is Motion Dialogue is actually a virus, since it's a 20 year old binary file in a format that a modern computer won't recognize. In fact, both my computer and the Kollmorgen rep's computers actively tried to sabotage emailing and opening it. In order to run the file, I had to obtain a DOS emulator such as DOSBox (freeware). In DOSBox, you need to edit the .conf file so that the com ports are actually enabled. By default, the COM ports are dummies and don't actually talk to anything. You will also need to go into the advanced settings for your computer's COM ports to re-assign your USB to RS232 connection to the same port that Motion Dialogue is listening to. Once all of these things were done, I was able to activate the SC750.
I hope this ends up being helpful to some other poor fool who ends up with a similar legacy project.
