146 Rockwell Automation Publication MOTION-UM003K-EN-P - January 2019
Chapter 7 Axis Scheduling
Axis Scheduling is compatible with these products:
• ControlLogix® 5580 controllers
• GuardLogix® 5580 controllers
• CompactLogix™ 5380 controllers
• Compact GuardLogix 5380 controllers
• ControlLogix 5570 controllers
• GuardLogix 5570 controllers
• CompactLogix 5370 controllers
• Compact GuardLogix 5370 controllers
• All Integrated Motion EtherNet/IP™ drives, for example, Kinetix®,
PowerFlex®, and other third-party drives
About Axis Scheduling
Axis Scheduling can improve ControlLogix and CompactLogix EtherNet/IP
Integrated Architecture® Motion system performance by reducing average
Logix controller and EtherNet/IP network utilization. Axis Scheduling
supports three separate controller/network motion drive update rates per
controller, one rate for high-performance drives, and two additional rates for
lower performance drives.
For example, suppose that you have a robot that removes product from a
conveyor belt. There are three precision axes on the robot and four general-
purpose axes on the conveyor belt. If you configure the controller to run all
seven axes at 2 ms to control the precision axes, this setting takes the network
utilization of your controller too high. In the past, one option would have been
to run all seven axes at 8 ms, but this setting is not fast or precise enough for the
robot axes. So you have had to add a second controller and Ethernet module to
get the performance you needed. Axis Scheduling lets you configure the axes at
different rates that are based on the needs of the application, which balances
the motion performance and network utilization of your controller.
With Axis Scheduling, you can configure the axes on the robot to run at a
faster base-update rate (2 ms) than the rate of the conveyor (8 ms).
With the ability to configure three update periods, the four conveyor axes can
run as one channel, which appears to the controller as one drive. The axes are
updated round-robin style; every 2 ms, three of the robot axes and one of the
conveyor axes are updated.
During the next update, three robot axes are updated and then the next
conveyor axis is updated; eventually all conveyor axes are updated and the
process starts again. The controller updates four axes every update period. The
controller can handle the load of four axes easier than a load of seven axes. This
capability improves the performance of the controller.
To Next Page
Loading...
Need help?
General
