Yep. Correct. 1K was when I was thinking of using 256 steps but even then it would be 512Hz. Not sure where I got 1K from.
Obviously I need 128Hz.
I could possiblt do 64 timed pulses but I also need to consider the change of direction. At any time during the output the demand to go in the opposite direction could occur. I will be monitoring 2 inputs, if one is higher than the other (they will be either 0V or 5V or the other way around) then the output either increases or decreases.