I think I’m DigiPower means or refers to this as digital Servo Zoom control, not that all the remote functions are digital vs analog. I believe it is still an Analog protocol controlled lens, as all SD ENG lenses were. Does the focus Servo control work from the camera, yiu do have the zoom and focus Servo selector on then lens set to “S” mode, which is Servo.
Without a ATEM connected, then see if the camera can control focus, by pressing the focus button, see manual:
Control and Playback Buttons
Focus
When using a B4 or EF lens supports electronic focus adjustments, press the ‘focus’ button to activate auto focus. A white focus square will appear on the fold out monitor. Anything within the square will be correctly focused. When the lens is focused, the square will disappear.
NOTE To use the 'focus' button, your B4 lens must have servo focus control, with the servo activated. See the 'getting started' section for more information.
If this works, then the focus Servo is working.
On the ATEM, can you control any of the camera settings? Make sure you have a camera ID no set on the camera and the same number set on the ATEM, again check the UM Broadcast manual for details.
If everything is set correctly, and you still do not have control, contact BM Supoort directly. Also,see if yiu can get access to a B4 ENG camera, like a Sony or Panasonic, and see if the lens works on that camera, to double check the lens is actually working correctly. A lot can go wrong with used SD ENG lenses, while it may look newish, or not thst used, the Servo controls have mechanical systems thst wear out with use.
This is why, I stay away from any lens that is well used looking, and prefer to get newer ENG lenses, when servos are part of the kit, they do wear out. See Kim’s post above about lens Servo units.
Cheers