dio_move_step_motor

	status.i4.v = dio_move_step_motor(di_motor.i4.r, di_status.i4.r, 
					  set_value.r4.r, tolerance.r4.r,
					  num_iterations.i4.r, on_count.i4.r
					  [,update_func.f.v])

	This routine sets a stepping motor, with a servo loop, to make it go
	to the desired position.  The motor will be sent to desired value
	+/- a tolerance.  If desired the motor will be reset and turned on
	(if it trips off).  You can also set the number of iterations to try
	to get to the desired position.  This routine will also check for user
	abort (user needs to setup with the routine abort_init and cancel
	with abort_cancel) and return an error if one is seen.

	di_motor	device index of the motor you're moving
	di_status	device index for "steps remaining" device in the C057
	set_value	desired position; in engineering units
	tolerance	allowed error in desired position; move will be 
			considered successful if it gets to a position of 
			"set_value" +/- "tolerance"
	num_iterations	number of times you'll allow retry of sending
			"set_value"
	on_count	number of times you'll allow reset and on for a motor
			that's tripped off
	[update_func]	if specified this function will be called periodically;
			this allows the user to update during the move
			(default is NULL)

	This function returns ACNET status values as follows:

	OK			success
	DIO_SMOFF		stepping motor is off
	DIO_SMITER		motor iterations used up
	CBS_ABORT		user aborted the move
	negative value		ACNET format error

	This function requires the following include files:

	diolib_h, acnet_errors_h

	Related functions:

	dio_is_step_motor, dio_set_step_motor(_c), dio_set_step_motor_steps_c,
	abort_init, abort_cancel

	C/C++ usage:

	int	status;
	int	di_motor = 5122;
	int	di_status = 5122;
	int	num_iterations = 2;
	int	on_count = 1;
	float	set_value = 100.0;
	float	tolerance = 0.5;
	void	update_func(void);

	status = dio_move_step_motor(&di_motor,&di_status,&set_value,
				     &tolerance,&num_iterations,
				     &on_count,update_func);