Why Can’t I Switch My EtherCAT Chassis' I/O Scan Mode from Configuration Mode to Active Mode?

Updated Nov 7, 2023

Reported In


  • NI-9144
  • NI-9145

Issue Details

I have an EtherCAT System I am trying to switch between Configuration Mode to Active Mode in the LabVIEW Project Explorer Window.  When doing this, LabVIEW returns a message saying:

 An error occurred while attempting to switch the I/O scan mode.  The distributed clock could not be enabled because the master could not read the network topology.  This could be caused by the slave device having an improper connection to the network .

When I attempt to change the EtherCAT mode programmatically in LabVIEW using code similar to the snippet, I get the LabVIEW error -2147138509.


Why am I getting these errors and how can I successfully switch my EtherCAT Chassis form Configuration Mode to Active Mode?


This error is typically seen when multiple EtherCAT Chassis are daisy chained.  When setting up these systems, you will need to connect the Ethernet port labeled “Out” on one slave to the Ethernet port labeled “In” on the next slave for it to work correctly. LabVIEW will display this error if these ports are wired incorrectly.  Therefore, in order to successfully switch modes of your EtherCAT system, ensure your chassis are properly connected together.
Note: This error can also be seen when the firewall settings on the computer interfere with communication to the EtherCAT slaves. If you have checked that the ports are connected as outlined above and are still seeing the error, try turning off all firewalls on the computer and connect again.