Rockwell Automation 1771-QC , D17716.5.25 SER/B SERVO POS - Manual (Page 9)

Introducing the Servo Positioning Assembly
Chapter 2
2Ć3
Figure 2.2
ClosedĆloop Axis Servo System
Axis Motion
Motor Tach Encoder
PC
Processor
Servo
Drive
Velocity
Feedback
Discrete Inputs:
Jog Forward
Jog Reverse
Home Limit Switch
Hardware Stop
Hardware Start
Feedrate Enable
Discrete Output:
Hardware Done
Tach Input for
Loss-of-Feedback
Detection
Drive
Disable
Command
Position Data
Status
Block
Velocity
Command
Servo Controller
(cat. no. 1771 -M3)
Servo Expander
(cat. no. 1771 -ES)
NOTE:
A second and third Servo Expander Module
could be installed in this I/O chassis for control
of a second and third axis.
Position
Feedback
10998
The PC processor sends commands and user-programmed data from the
data table to the 1771-M3 controller as directed by a block-transfer write
instruction. The 1771-M3 controller coordinates the block transfer
automatically, keeping ladder diagram programming to a minimum.
Based on information it receives from the processor, the 1771-M3
controller sends axis motion commands to the 1771-ES expander.
The 1771-ES expander closes the servo positioning loop. It commands
axis motion by generating an analog voltage for your servo drive. Every
2.4 milliseconds (ms) it updates this analog output voltage according to
motion commands from the 1771-M3 controller, discrete inputs, and