The lines on the DIO port respond to trhe MOMO (Must On, Must Off) protocol which is a tri state protocol. This allows each line on the DIO ports to be used individually. The lines, however, are by default static DIO which means that if you want to create a pulse train in them you must do it through a software routine where you change the states every time the set dio port momo call is executed. Another option is to use the PWM ouptut lines available on this port. You can use the lines specified as PWM outputs (check the 7344 hardware manual for this) so that in MAX you can generate a continous pulse train and then you can use NI-Motion's PWM fucntions to control the frequency and duty cycle of the train.
