Rockwell Automation 2080-LC50 Micro830 and Micro850 Programmable Controllers User Manual - Manual (Page 94)

80 Rockwell Automation Publication 2080-UM002F-EN-E - December 2013
Chapter 7 Motion Control with PTO and PWM
Limits
The Limits parameter sets a boundary point for the axis, and works in
conjunction with the Stop parameter to define a boundary condition for the axis
on the type of stop to apply when certain configured limits are reached.
There are three types of motion position limits.
• Hard Limits
• Soft Limits
• PTO Pulse Limits
If any one of these limits is reached on a moving axis (except on homing), an over
travel limit error will be reported and the axis will be stopped based on
configured behavior.
Hard Limits
Hard limits refer to the input signals received from physical hardware devices
such as limit switches and proximity sensors. These input signals detect the
presence of the load at the maximum upper and minimum lower extents of
allowable motion of the load or movable structure that carries the load, such as a
load tray on a transfer shuttle.
Hardware limits are mapped to discrete inputs that are associated with data
tags/variables.
When a hard limit switch is enabled, the axis comes to a stop when the limit
switch is detected during motion. If hard stop on hard limit switch is configured
as ON and the limit is detected, motion is stopped immediately (that is, PTO
pulse is stopped immediately by the hardware). Alternatively, if hard stop on hard
limit switch is configured as OFF, motion will be stopped using Emergency Stop
parameters.
TIP See Motion Axis Configuration in Connected Components Workbench on
page 89 for information on how to configure limits and stop profiles and
the acceptable value range for each.
Sample Limits configuration in Connected Components Workbench