If you are calling one rev of the motor as 1 unit then 426,666/3,200 will be the steps per unit.
Hood

Edit sorry thats wrong, if 2000 line encoder thats 8000 per rev so if one rev is one unit then its 8000

again a little confused !!! cant we turn this servo continuous 3200 Rotation Per Minute ?? or 533.333 Rotation Per Second ?

if i set 8000 to "step per" it means that it will turn 3200 RPM right ? (for this calculation)

If you set the steps per at 8000 that means when you command a move of 1 unit per minute the motor will turn one revolution in one minute and the pulses sent out will be 8,000 per minute.
If you command a speed of 3,200 units per minute then that will be 8,000 x 3,200 = 25,600,000 pulses sent out per minute or 426,666 pulses per second.

Hood

Is this a spindle motor?