Actually, I'll be using mine with UCCNC and a UC300ETH, but everything should be similar to the ESS.
I thought I understood how the speed control worked from the manual, but looking again, yes,it's confusing.
Which pin is the PWM signal? And why do you need an output pin to output the analog voltage? Usually that's not part of the motion controller.
Hopefully I'll get it tomorrow or Saturday, so I can start playing as well.