User`s manual

16-4 Motion Mate™ DSM314 for Series 90™-30 PLCs User's Manual – January 2001 GFK-1742A
16
Basic Cam Shapes/Definition
Electronic Cams duplicate the behavior of their mechanical counterparts. The following figure
illustrates the elements of a basic mechanical cam system and shows the Slave Position for two
positions of the Master Cam. As the Master Shaft rotates, the Master Cam, which is fastened to the
Master Shaft, rotates as well. The Cam Follower (which is a ball bearing mounted to the Offset
Link Arm) rolls on the Master Cam as the Master Cam rotates. The Cam Follower either pushes up
or pulls down on the Offset Link Arm, depending on the position of the Master Cam. The Lever
Arm, which is coupled to the Offset Link Arm, moves up and down in turn, pivoting on the
Fulcrum as the Offset Link Arm moves. Besides the Master Cam shape, additional parameters that
affect slave motion are the Cam Phase value (the amount that the Master Cam position is offset
from the Master Shaft position), the Offset Length of the Offset Link Arm, and the Follower
Amplitude (based on the Fulcrum position). These mechanical parameters all have Electronic
Cam counterparts.
M
aster Cam
F
ollower
A
mplitude
Slave
Position
Cam
Phase
O
ffset
L
ength
M
aster
S
haft
C
am
F
ollower
F
ulcrum
Offset
Link Arm
L
ever Arm
M
aster Cam
F
ollower
A
mplitude
Slave
Position
O
ffset
L
ength
M
aster
S
haft
C
am
F
ollower
F
ulcrum
Offset
L
ink Arm
C
am
P
hase
L
ever Arm
Figure 16-5. CAM Model