Omron SYSMAC CJ Series, Operation Manual

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How-to’s Section 5-1
283
Example 5
With the feedforward set to 100%, the Following Error is very small and
proportional to the acceleration. The optimum value of 100% correction is the
maximum value that can be set. The parameter value of Pn109 is easier to set
than the parameter value of VFF_GAIN.
The parameter values for the example are:
/i
5-1-3 Setting the UNITS axis parameter and gear ratio
In controlling the mechanical axis with the CJ1W-MCH72, a Servo Driver and
a servo motor, the only measurement units that the hardware understands are
encoder counts. All commands to the driver to move an axis are expressed in
encoder counts. All feedback information about axis positions is also
expressed in encoder counts. When writing programs in BASIC to achieve
movements or a sequence of movements, a user can prefer to work with user
defined units, such as millimeter, centimeter, meter, degree of angle,
"product", "rotation", "stations". The
UNITS axis parameter contains the
conversion factor between encoder counts and user defined units. All axis
parameters related to motion and arguments of axis commands that determine
the amount of motion are expressed in these user units. This parameter
enables the user to define the most convenient units to work with. For
example, for a moving part that makes a linear motion, you can prefer mm, or
fraction of mm. For a moving part that makes a rotation motion, you can prefer
a degree of angle or its fraction. For more information on the
UNITS axis
parameter, see section 4-2-246.
Motion Parameter values
Fn001=6
Pn109=100