Project 06/2005
Danaher
Motion
64 Rev
E
M-SS-005-03l
The motion program cycles axis A1 10 times. Most of this main program is
commented out because this code enables the drive and generates motion
commands. Remove the single-quote comment markers for the program to
run. These lines are commented out because to ensure that it is safe to
operate your machine before executing this program. This includes tuning
your axes properly to assure stable motion control. Refer to the
SERVOSTAR
®
MC Installation Manual
for more information.
The third section of the auto setup program is a SERCOS setup subroutine.
This subroutine brings up the SERCOS ring in preparation for the drives
being enabled. The final section of the auto setup program is the axis setup
subroutine. This subroutine loads axis properties for units and limits. Refer to
Appendix A for a Sample Nesting Program.
3.6.6. User
Units
The MC supports user units with one floating-point conversion factor for each
of six types of properties: position, velocity, acceleration, jerk, external
position, and external velocity.
<axis>.DIRECTION
is applied as a multiplier to the units conversion factors.
The movement factors (
i.e.
,
POSITIONFACTOR
,
VELOCITYFACTOR
,
ACCELERATIONFACTOR
) are only assigned positive values and
DIRECTION
determines their sign.
DIRECTION
can take one of two values:
-1 for forward direction or +1 for reverse direction.
MC units allow you to work in units that are convenient. All unit types are
independent, so position units are inches, velocity units are feet/min and
acceleration is rpm/second. Units are changed only when the axis is
disabled.
3.6.7. Position
Units
Position units are controlled by
POSITIONFACTOR
or
PFAC
. The MC
internal units are encoder counts for encoder-based systems or 65536
counts per revolution for resolver-based systems. Encoder counts are four
times encoder lines. To set up position units, determine how many counts
are in one of your selected units. For example, suppose you had this system:
Desired units: inches
Rotary motor (as opposed to linear motor)
2000 line Encoder
3:1 gearbox
5 turn per inch ball screw
Determine
POSITIONFACTOR
(number of counts per inch):
1 inch = 5 turns on the screw
= 15 turns into the gearbox
= 15 * 2000 lines
= 15 * 2000 * 4 counts
= 120,000 counts
POSITIONFACTOR
is set to the number of counts per inch: 120000.
A1.PositionFactor = 120000
For a second example, let’s change the first example from encoder to
resolver, change the ball screw and use meters for the units:
Desired units: meters
Rotary motor
Resolver (65536 counts per revolution)
3:1 gearbox
2 turn/cm ball screw