Manual

Positioning with Allen-Bradley PC
Chapter 4
411
Figure 4.9 shows an example of an axis and its position scale. Any axis
position within the range of travel can be identified by a number. For the
servo positioning assembly, the axis position scale can be either in inches
or millimeters.
The position scale is an internal scale used by the servo positioning
assembly to identify axis position. It is not printed on the axis slide. You
can shift the axis position scale by entering (through the command block)
any of the following commands:
search home
preset
initialize home
Figure 4.9
Axis
Position Scale
21 3 4 5 6
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150MM
INCHES
0
17967
Search Home
Because the position feedback is incremental rather than absolute, the
servo positioning assembly does not know the axis position when it first
receives power. You must command a search home (through the
command block) each time after powering up. In the search home
operation, the axis moves until the servo positioning assembly detects the
first encoder marker beyond the user-installed home limit switch. The