AC500 PLCs (PM585 and PM59x) can be used to perform real-time motion control of ABBs EtherCAT enabled servo drives. In some applications it is necessary to synchronize the motion of these drives to a master encoder (e.g. cut to length applications using a lay-on encoder to track the movement of the material to be cut to length).
This application note details how to use Automation Builder to define the hardware setup suitable for use of any available encoder channel on a connected MicroFlex e190 or MotiFlex e180 servo drive as a master encoder and how to then use the encoder value provided by the drive to create a (virtual/simulated) master axis in a PLCopen motion application. This offers some performance benefits over the use of a CD522 2 channel encoder module…
· Encoder input frequency extended up to 8MHz (quadrature), depending on encoder channel used, compared to 300kHz for the CD522
· Encoder position update synchronized with EtherCAT cycle (leading to smoother motion from geared axes)
· Ability to filter touchprobe (latch) data via drive parameters (leading to faster and simpler PLC application code development)
This document also details how the touchprobe function block included with the PS552-MC-E motion libraries can be used in combination with the e190 and e180 drives to latch a connected master encoder position. A sample Automation Builder project is included to illustrate all of the topics covered by this application note.