How Can I Communicate with my NI 9145 EtherCAT Slave Chassis?

Updated Apr 20, 2023

Reported In


  • NI-9145

Issue Details

I have to communicate with a NI 9145 EtherCAT expansion chassis. What are the different options I have available to do so ?


To communicate with an EtherCAT chassis, you will either have to use the Scan Interface mode to interact directly with the I/O of your slave device, or you will have to create User Defined Variables in the FPGA VI that you upload to your EtherCAT slave, to enable the Scan Engine to read or write in those variables. Either way, the communication always relies on the scan engine, and there is no way to use FIFOs to work with the NI 9145.

Additional Information

Even though the following document is written for the NI 9144, you will find more information that can be applied to the NI 9145 here: Communication between NI 9144 EtherCAT Chassis and Real-Time Controller