Parker Hannifin HD130, HD65 manual MS20 Microstep Card, Description, Setting Up Microstep Card

HD65 & HD130 STEPPER DRIVES USER GUIDE 15

MS20 Microstep Card

Description	The HD65M and HD130M drives are fitted with the MS20 Microstep
	Card which gives improved resolution and smoothness from a
	standard motor. Microstepping is achieved by proportioning the
	currents in the two motor windings so that the rotor takes up a series
	of intermediate step positions. In this way a standard 200-step
	motor may be made to perform 1000 steps/rev (1/5 step mode), or
	2000 steps/rev (1/10 step mode).
	Ideally the intermediate current levels will produce equally-spaced
	step positions as well as equal dynamic torque, without exceeding
	the dissi-pation limit of the motor. In practice this can be difficult to
	achieve and a compromise has to be made. If the current levels are
	plotted against rotor position the resulting profile resembles a
	sinusoidal shape. The optimum profile varies from one type of motor
	to another, and for this reason the MS20 card has a selection of 64
	alternative profiles which are stored in an Eprom and selected by an
	8-position DIL switch. This switch is accessible between the two
	edge connectors at the rear of the drive. The card has been
	programmed with a set of profiles which have been derived
	theoretically.
	A sinusoidally-based profile is obtained with all bit switches in the
	"off" position. Switches 2 - 6 may be used to set in an increasing
	binary number which will cause the profile to progressively "fill out"
	from a sinewave (switch 2 is the least significant bit). By turning on
	switch 7, increasing the number in switches 2 - 6 will then trim the
	profile down towards a triangular shape. In practice this tends to be
	more useful than the "filled out" form. Switches 1 and 8 should be
	left permanently off.
	A few examples are shown below						-	a "1" indicates that the switch is
	"on" .
			Switch position							Profile
	8	7	6	5	4	3	2		1
	0	0	0	0	0	0	0		0	Sinewave
	0	0	0	0	0	0	1		0	Slight fill-out
	0	0	1	0	0	0	0		0	Moderate fill-out
	0	0	1	1	1	1	1		0	Maximum fill-out
	0	1	0	0	0	0	1		0	Slight trimming
	0	1	1	0	0	0	0		0	Moderate trimming
	0	1	1	1	1	1	1		0	Maximum trimming

Setting Up the

Microstep

Card

Link 1 on the microstep card should be left in position "a". This link is provided for future implementation of an alternative profile in boost.