Poth button movements work as poth wants them to. It has nothing to do with the pmc8. But you are not incorrect, those poth buttons are a waste.
Nina buttons are different. They move the mount RA axis with the east west buttons and the dec axis with the north south buttons. And they move it at a rate. This is more in concert with the way my mind works when it comes to the buttons.
Poth buttons move the telescope line of sight to the East, west, north or south by the number of degrees denoted in the distance drop down box. The amount of movement needed on either axis to affect a line of sight change of a fixed amount is dependent upon where the scope is pointing (on an equatorial mount such as ours). Thus the movement might not be what you think, especially when looking north. Also I believe the Poth button is designed to move the mount the designated number of degrees with a single button press, thus you must hit the stop button if you want to stop before the mount achieves the desired move. Nina buttons are simple— motor run with button down, motor stop with button up.
So in summary the pmc8 is always doing what it is told. The Poth buttons are not doing what you expect because your expectations are incorrect. But hopefully the above will help you understand the deal.
I hate Poth button too, and pretty much never use them. It’s a club with a lot of members!
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired