rt ni-9148 how to build a distributed measuring system

[przemmo]

Hello!

I am just planning to build such a system based on cRIO 9014 and 9148. My problem is that I do not know how to connect these two devices by Ethernet. The 9148 chassis cannot be added to  cRIO9014 (it can have only one chassis). All I/O modules of 9148 chassis are handled by FPGA, and it is FPGA to read data from these modules. How so send these data over Ethernet to other cRIO controller?

Is there any training or technical sheet touching it?

There is something I do not know about.

Help,

Przemek

[Virdzs · Accepted solution]

Hi przemmo,

I think this tutorial will be useful for you:

Getting Started with the NI 9148 Ethernet RIO Expansion Chassis

If you need more details, just let me know!

Gábor

[przemmo]

Hello Virdzs,

You detailed the plan at length, the rest I know. Though I have the last question.

How to detect modules connected to the chassis from software running on the FPGA. I want to let user to choose modules for use. Fer example one time he would like to measure only voltage using module connected to slot 0, and other time he may want to use two modules or 5 modules.

[Virdzs]

Hi przemmo,

There is some limitation in situations like this. If you build an FPGA application you can use only one modul type in one slot. But it is changeable any time (hot swap if module supports).

So if you want to use only one module type in all slot you can easily do it, you can add them to the project even if they are not present. But you can't detect the changes from software. If you remove one module the FPGA program will show you the last values from that module (if it is an input one). But you can provide option on user interface to turn in or out modules. I used this small FPGA code in my test:

I hope it helps! Have a nice day!