User manual

115Publication LOGIX-AP010B-EN-P - May 2010 115
Chapter 7
Drive and Loop Control
Encoder/Positioning
Modules
These are intelligent I/O modules that can calculate the position of a rotary or
linear axis based on electronic encoder input signals. The module then
processes this information to calculate and produce the required output for
the positional control of speed drives.
The modules determine the position of a rotary cam by counting and
processing the high speed pulses generated by an encoder. These high speed
pulses are connected to the input channel of the module.
These pulses are at too high a frequency to be processed by standard digital
input modules. The encoder/positioning modules are rated for pulse input
signals up to 500 kHz, while a standard digital input module is suitable for
counting pulses up to a maximum frequency of 100 Hz.
Furthermore, the modules have their own microprocessors that allow them to
handle these position control tasks autonomously thus reducing the load to the
S5 central processor.
Logix Servo Drive
Controllers
The Logix controllers use a range of modules called SERCOS interface
modules that serve as a link between the Logix platform and intelligent servo
drives.
The SERCOS interface is an open, controller-to-digital drive interface designed
for high-speed, real time, serial communication by using noise-immune,
fiber-optic cables.
The following Logix Motion Interface Modules can be used to control
servomotors.
• 1756-M16SE
• 1756-M08SE
• 1756-M03SE
• 1756-M02AE
• 1756-HYD02
• 1756-M02AS
Using these modules and the RSLogix 5000 motion instruction set, detailed
drive-status information can be sent from drive to controller and from
controller to drive.