Rockwell Automation 8720MC Drives Integration Manual - Manual (Page 51)

Publication 8720MC-IN002A-EN-P — December 2002
Commissioning Your 8720MC Analog Drive 2-19
4. Navigate to Parameter 154, “Orient Options” and select an orient
direction. The application will dictate this choice. The available
options are “CW”, “CCW” or “Shortest Pth”.
5. Enable the drive.
6. Toggle the orient request input, P5-32, to a true state or navigate
to Parameter 152, “Spin Orient Req” and select a state of “1” and
press ENTER.
The motor will rotate in velocity mode in the selected direction at
the selected orient speed until the encoder marker is detected.
The drive will then transfer to positioning mode and calculate the
desired end point of zero motor offset angle and zero
programmed angle. Regardless of the orient direction chosen, with
the end location at zero counts the motor will stop and return via
shortest path to the marker and stop.
To change the motor position to the desired zero angle, Parameter 150
“Mtr Marker Ofset” must be modified to reflect the difference between
the actual zero angle and the desired zero angle.
1. To determine the motor marker offset first orient the spindle with
zero in Parameter 150. Navigate to Parameter 51, “Mtr Posn Fdbk”,
and the position value displayed will be zero in counts.
2. With the drive disabled, rotate the motor to the desired motor
angle and record that position.
The required correction angle is the difference between the marker 0
angle reading and the desired angle 0 reading for the application.
Signs are very important in determining offsets. Make sure to record if
the position value increased or decreased. Viewing from the drive end
of the motor, for standard configurations, CCW (or -) rotation
decreases parameter 51. CW (or positive) rotation increases parameter
51. Parameter 150 has the opposite sense since it is subtracted from
the position. Therefore if the desired offset direction is CW it should
have a minus value. Conversely ccw offset should have a positive
value.
To prevent reversals in direction during orient it is good practice to
make the direction of the offset the same as the direction of the
selected orient rotation. That is if the orient direction is CW the offset
angle should be CW. If the orient direction is CCW the offset angle
should be CCW. Accordingly it may be necessary to calculate the
IMPORTANT
Because the motor is randomly assembled to the
mechanical system this is probably not the actual
orient position required for the application.