Rockwell Automation 57C422B 2 Axis Servo Module - Manual (Page 78)

4-50 2-Axis Servo Module M/N 57C422B
In order to select the value format (bytes or words), you need
to consider the number of points that are required to
represent the profile and the largest value that will be
required. In general, a profile can be described more
accurately with more points. The largest value that can be
stored in the table when time cam is selected can be
calculated using the following equation:
largest value = speed * encoder * time * .00125
where: speed = max. axis velocity in eng. units/sec
encoder = encoder counts/eng. unit
time = the value in register 129
If the absolute value of the above calculation exceeds 127,
you must choose the word format.
Position Cam
Register 38, bits 0 and 1 define what the axis will follow for
the purposes of position-based cam. Register 125 selects
the master axis position increment, i.e., the amount of travel
the master moves to increment to the next position in the
table, thus resulting in all points being the same distance
apart. Position cam values must be in double precision
integer format (32 bit values). Note that there are 956 total
points possible. For the X axis, register 2044, 2045 is the last
possible point in the cam table. For the Y axis, register 4092,
4093 is the last possible point in the cam table.
Linear Mode: When the master axis and the axis under
control are configured for linear mode in register 0, the
position cam operates in linear mode. In this mode, the first
point in the table should have a value of 0.