Rockwell Automation 8520-ARM2 9/Series CNC AMP Reference Manual Documentation Set - Manual (Page 201)

Servo Parameters
Chapter 7
7-55
between Teeth on Gear for Position Feedback and the parameter Teeth
on Lead Screw should be one to one. For example if the linear device has
5000 lines per 1/2 inch enter 5000 as the Position Feedback
Counts/Cycle and .5 inch as the Lead Screw Thread Pitch. Both Teeth
on Gear for Position Feedback and Teeth on Lead Screw for Position
Feedback can then be set to one.
In some cases, there may be a series of gears or gearbelt pulleys that make up a
final gear ratio for a servo. In this case, it is necessary to factor this gear ratio
into this parameter and the parameter Teeth on Lead Screw for Pos FB.
Important: The system automatically reduces the gear ratio to the lowest
common denominator. For example, a ratio of 44:40 will be reduced to
11:10 on an AMP upload.
Figure 7.31
Typical Nonmotor--mounted Position Feedback Configuration
Axis
Lead screw
thread pitch
Teeth on gear
Servo
motor
Encoder
(position
feedback) Encoder
(velocity
feedback)
Teeth on lead screw