Why Can't I Access All the Input and Output Variables of My Third-Party EtherCAT® Slave in LabVIEW?

Updated Sep 14, 2022

Reported In


  • NI-Industrial Communications for EtherCAT

Issue Details

I have followed the steps in the Adding Third-Party EtherCAT® Slaves in LabVIEW  article and added the EtherCAT slave to my LabVIEW project. Why can't I see all the I/O variables for this slave in my LabVIEW project?


This issue can be caused by older XML files that interfere when importing a new file. To resolve this follow the steps below:


  1. Navigate to the folder that contains the imported files. The XML files can be located in one of these folders: 
    • C:\Program Files (x86)\National Instruments\Shared\IndComECAT\DD 
    • C:\Program Files (x86)\National Instruments\LabVIEWXXX\resource\Framework\Providers\indcomecat\DD
  2. Delete unused XML files. If possible, delete all the XML files to ensure a clean import.
  3. Restart LabVIEW.

Real-Time Target

  1. The XML files are also stored on the Real-Time Target, you can use any sFTP client to navigate to these folders:
    • /ni-rt/system/IndComECAT/DD/ for VxWorks and Phar Lap RT Targets
    • /var/local/natinst/IndComECAT/DD/ for NI Linux RT Targets
  2. Delete unused XML files. If possible, delete all the XML files to ensure a clean import.
  3. Restart the target and re-import the XML files.

XML Format

This issue can also be caused by unnecessary space characters being present before and after the Input/Output element names within the third-party XML file. This is the case even when you follow the proper procedure for adding a third-party slave to your project. 

Follow the steps below to remove the unnecessary space characters from the XML Device Profile:
  1. Open the XML file that contains your EtherCAT Device Profile in Notepad.
  2. Select Ctrl+F on your keyboard to open the Notepad Find window.
  3. Type <\Name> in the Find what: field followed by selecting Find Next.
  4. Continue selecting Find Next whilst monitoring the element text between each <Name> start-tag and <\Name> end-tag.
  5. Remove any space characters at the beginning or the end of the element text, for example replace <Name> Digital Inputs </Name> with <Name>Digital Inputs</Name>.
  6. When the end of the XML file is reached save the changes to the file by selecting File»Save in Notepad.
  7. Import the updated XML file into your LabVIEW Project.
  8. You will now be able to access the Input and Output Parameters in LabVIEW.