User`s manual

Using the Electronic CAM Feature
GFK-1742A Chapter 16 Using the Electronic CAM Feature 16-15
16
travel for the driven load. In our example, the motor connected to the driven load has an encoder
that produces 8,192 counts per motor revolution. Thus, 8,192 feedback counts equals 1 inch of
load travel. Some users would find it easier to program motion in inches rather than in feedback
counts. In our case, we could set up our scaling such that we can program motion in thousandths of
an inch. To obtain this result, we want our User Units to Counts ratio to be 1000 to 8192. The user
would specify this value in the DSM hardware configuration. Additional information on specifying
these values is located in Chapter 5.
The CAM feature also supports application-specific units. However, you are required to manually
transfer the values entered in hardware configuration to the appropriate area within the CAM
editor. Note: You must transfer these values for both Master and Slave axes. Building on our
prior example, suppose both the master and the slave axes had equivalent motors. Therefore, each
feedback device has the same 8,192 counts per revolution. However, for the master, one motor
revolution equals 1 inch of load travel, while for the slave, one motor revolution equals .5 inches of
load travel. To make our programs easier to understand, we want to program the master and slave
in the same units. In our case, we have chosen to program in units of 0.001 inch. To obtain this
result, we need to first determine the correct user units to counts ratios for the master and the slave.
To determine our ratio, we apply the following equation
Revolution Motor Per Counts FeedbackResolution Desired
Rotation Motor per Movement Load
Counts
Units User
1
⋅






=
For the master axis in the example we have
Counts
in
Counts
Units User
Counts
in
Counts
Units User
⋅






8192
1000
=
8192
1
⋅












1000
1
1
=
For the slave axis in the example we have
Counts
in
Counts
Units User
Counts
in
Counts
Units User
⋅






8192
500
=
8192
1
⋅












1000
1
5
=
.
You then need to enter these values in the appropriate locations in hardware configuration. In our
example, Axis #2 is the master and Axis #1 is the slave. Therefore, we enter the User Units and
Count values into hardware configuration for the slave as shown in Figure 16-8.