Allen-Bradley Micro830, Manual

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Rockwell Automation Publication 2080-UM002K-EN-E - March 2019 81
Chapter
7
Motion Control
Generally two types of motion control are used in Micro800 controller motion
applications which have Kinetix 3 servo drives.
•
Indexed Motion – Micro800 controller issues position indexes to the servo
drive using Modbus RTU communications or discrete I/O. Used for
simple positioning. See publication CC-QS025 for building block
example.
•
PTO Motion – Micro800 controller uses pulse and direction outputs to
the servo drive for precise control of position and velocity with Modbus
RTU communications or discrete I/O for feedback. Micro800 motion
configuration and instructions makes programming easy. See publication
CC-QS033 for building block example.
PTO Motion Control
Certain Micro830, Micro850, and Micro870 controllers (see table below)
support motion control through high speed pulse-train outputs (PTO). PTO
functionality refers to the ability of a controller to accurately generate a specific
number of pulses at a specified frequency. These pulses are sent to a motion
device, such as a servo drive, which in turn controls the number of rotations
(position) of a servo motor. Each PTO is exactly mapped to one axis, to allow for
control of simple positioning in stepper motors and servo drives with
pulse/direction input.
As the duty cycle of the PTO can be changed dynamically, the PTO can also be
used as a pulse width modulation (PWM) output.