EtherCAT PDO and SDO Interpretation in LabVIEW Programming Environment

Updated Oct 11, 2024

Reported In

Software

  • LabVIEW

Driver

  • NI-Industrial Communications for EtherCAT

Issue Details

How do we interpret EtherCAT Process Data Objects (PDOs) and Service Data Objects (SDOs) in the LabVIEW programming environment? 

Solution

You can see below the common EtherCAT terminologies and their interpretations in the LabVIEW API:
  • Master – The only node that can send an EtherCAT frame.
  • Slave  – Each slave reads data addressed to it and inserts its data in the frame as the data moves downstream.
  • Mailbox – A data link layer mechanism of EtherCAT used to exchange acyclic data between master and slave.
  • Process Data Objects (PDO) – Data updated each cycle (eg setpoints).
  • Service Data Objects (SDO) – Data updated occasionally (eg configuration).
  • Static variable reference – Created by dragging the variable from the project.  Used for PDO communication.
  • Programmatic variable reference – Created with an invoke node.  Used for SDO communication.
  • RSI – RIO Scan Interface.

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