03-17-2022 09:07 AM
Im looking for some advice on how to connect two of our NI Test rigs together over ethernet.
We have an integration rig with 4 x 16 slot PXI NI chassis system controlled with veristand. Here we have a RT computer running Pharlap linked to host PC with Veristand 2016.
On the same site , around 1KM away we have a second rig with 1 x 16 slot PXI NI chassis system controlled with veristand. Here we have a RT computer running Pharlap linked to host PC with Veristand 2016.
We would like to send data between the two rigs. How can this be best done? connection over the company ethernet network? If so, what time lag should be expected? From where would the ethernet communication take place? Between two RT computers or additinal ethernet PXI cards?
Thanks for any help and please let me know if Ive missed any information required to assess this.
03-17-2022 01:39 PM
I would recommend considering the purpose of connecting the two rigs. Is there a desire to treat the two as a single distributed system with the ability to map channels and share data directly? Or perhaps you want a single host and project receiving the data but do not require directly sharing data between the two RT controllers.
In either case, I would recommend reading through this white paper: https://www.ni.com/en-us/innovations/white-papers/10/creating-a-distributed-system-with-ni-veristand.... Synchronization will be vital in either situation considering that the RT controllers have their own clocks. This white paper provides more detail into why synchronization is important, and presents various scenarios and the typical solutions required.
For deterministically sharing data between targets, Reflective Memory was the primary recommended solution. VeriStand has built-in support for it, and there are also a few custom devices that can be used which offer certain benefits. If you are strictly looking at sharing data between targets without Reflective Memory, NI developed a UDP component for our Data Sharing Framework. I believe this only supports back to 2017 as a built version though, so you would need to build for a previous version. Alternatively, there are also some unsupported custom devices for other network communication (see UDP Data Link CD) that you could evaluate with VeriStand 2016.
Overall, there are quite a few factors to consider when building a distributed system in VeriStand. After reading through the white papers, I would recommend that you consider contacting support.