AKD BASIC User Guide | 3 AKDBASICLanguage
CAM.CORRECTDIR: Specifies the direction of the correction move that is done when a new
cam table is activated (by setting CAM.ACTIVATE = n).
CAM.ADDPOINT: Adds the specified “point” (master position and corresponding slave posi-
tion) to the cam table being created.
3.11.3 Cam Wizard
The Cam Wizard is designed to solve cut to length applications. The picture below shows a typ-
ical setup:
In this application, material is being fed beneath a rotary knife. The master encoder measures
forward movement of the material under the knife. The slave motor controls rotation of the
knife. In order for this to work properly, the slave motor must be controlled (as a function of
master encoder counts) so the blade of the rotary knife:
1.
Stays out of the way until the proper amount of material has passed
2. Accelerates so the speed of the knife matches the speed of the material during the
cut
3.
Decelerates back to the original speed until the material is almost in position for the
next cut
The rotary knife either accelerates or decelerates to match the speed of the material
in the cut phase, depending on whether or not the circumference of the rotary knife is
less than or greater than the length of the piece to be cut. You may need to inter-
change the terms ‘accelerate’ and ‘decelerate’, or simply think of them as signed quan-
tities.
AKD BASIC’s CAM.ADDPOINT statement specifies a cam profile as a mapping from master
position to slave position. The problem refers to relative velocities and accelerations. It is not
always clear how to get from velocity and acceleration to position.
The Cam Wizard was designed to make such applications easy to implement. You provide:
1.
The master positions corresponding to the length of material to be cut
2.
The slave positions corresponding to one complete rotation of the knife with respect
to the master positions
Once you have provided these three pieces of information, the Cam Wizard automatically:
1.
Generates a subroutine to create the cam table
2.
Generates a subroutine to activate the cam
Kollmorgen™ | March 30, 2012 44
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