While you configure the microstepping ratio on the MID, the quadrature encoder decoding is done on your 73xx motion control. Thus you don't have to configure anything on the MID, but you will have to set the correct values in MAX for stepper steps per revolution (which is 400 for a 1.8° stepper motor with 2x microstepping) and the encoder counts per revolution. If 200 PPR refers to the resolution of one encoder phase, the 73xx will read 4 x 200 = 800 counts per revolution, but you should check with the encoder's specs how to interpret this value.
While other ratios are supported too, for closed loop operation the ideal ratio of steps/rev and counts/rev is 1:1, as this provides the best accuracy and performance. A lot of general purpose stepper systems work with a 1.8° stepper and 10x microstepping (= 2000 steps/rev) and a 500 line encoder (= 2000 counts/rev with X4 decoding).
Kind regards,
Jochen Klier
National Instruments
