Working With A Digitizing Axis in PLCopen

This topic provides the basics of setting up a digitizing axis and describes how to accomplish some common tasks. See Common Axis Parameters for reference material.

• The digitizing axis reads the secondary feedback from the drive via EtherCATEtherCAT is an open, high-performance Ethernet-based fieldbus system. The development goal of EtherCAT was to apply Ethernet to automation applications which require short data update times (also called cycle times) with low communication jitter (for synchronization purposes) and low hardware costs parameter object 0x2050.
  
• The PLCopenA vendor -and product- independent worldwide association active in Industrial Control and aiming at standardizing PLC file formats based on XML Axis Data is setup as follows with the correct EtherCAT Address set (where the first EtherCAT slave is 1001, the second is 1002 and so on):
  
• The actual position in user units can be read with the MC_ReadActPos function block.
  
• The polarity of the feedback signal can be changed using AKD drive parameter FB2.DIR .
  
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  • If an Endat 2.2 device is being used, set FB3.DIR and change DRV.HANDWHEELSRC to 3 in order to tie the PDO index 2050 parameter that is read from FB2 to FB3.
• The position can be offset using the MC_SetPos function block.