User guide
Introduction    CME 2 User Guide 
12  Copley Controls 
Basic Attributes of All Servo Control Loops 
These loops share several common attributes: 
Loop 
Attribute 
Description 
Command 
input 
Every loop is given a value to which it will attempt to control. For example, the velocity loop 
receives a velocity command that is the desired motor speed. 
Limits 
Limits are set on each loop to protect the motor and/or mechanical system. 
Feedback 
The nature of servo control loops is that they receive feedback from the device they are 
controlling. For example, the position loop uses the actual motor position as feedback. 
Gains 
These are constant values that are used in the mathematical equation of the servo loop. The 
values of these gains can be adjusted during amplifier setup to improve the loop 
performance. Adjusting these values is often referred to as tuning the loop. 
Output 
The loop generates a control signal. This signal can be used as the command signal to 
another control loop or the input to a power amplifier. 
For more information on using CME 2 to set up and tune control loops, see Control Loops 
(p. 111). 










