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Embedded FPGA vi - Network shared variables not updating

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Hello,

I am working with an ethernet RIO 9149 for data acquisition. I use a hybrid programmation mode.

I have a very simple FPGA VI that I downloaded on the flash memory. I have used the LED indicator to show that my VI is running once the power of the RIO is on. Everything goes well, except that my network shared variables are not updated in the DSM ("no known values" displayed). However when I run the FPGA VI from my laptop only once and then stop and close it (with "interactive execution"), then my shared variables are updating in the DSM.

Any ideas why is that, and how can I make the RIO update shared variables automatically without having to run the VI once?

 

Many thanks.

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Update: when I run the FPGA VI from my laptop, it seems that it is only the "open fpga reference" that triggers the DSM to display my data. I have made a VI with this block only and it works. However I would like not to have to do that and have my data directly accessible from any client on the network.

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Accepted by topic author adrrienc

Hi,

 

I have done some testing and research and found out that this doesn't seem to be possible. It is important to note the difference between Network-Published Shared Variables (NSPV) and Network-Published I/O Variables.

 

The second one are 'user defined I/O variables' to communicate between FPGA and RT Host (RT Host not present in Ethernet chassis like the NI 9149). If these variables are checked to be network-published (possible in properties). They are accesible by VI's running on hosts in the same LabVIEW project, so you must run a VI to access them, as you mention. This is explained on following page I/O Variable for Custom FPGA I/O Data (FPGA Module or Real-Time Module):

https://zone.ni.com/reference/en-XX/help/371361H-01/lvioscanhelp/io_vars/#user_IOV

 

I haven't found a way without a host (RT host or Windows PC) running a VI. If you have a cRIO with RT host and have NPSV in the RT VI it is possible.

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Accepted by topic author adrrienc

Hello,

 

Thanks very much for having been through this. I have come to the same conclusion as well, it is not possible, and the device should be upgraded to one with a RT host. The use of a simple host VI containing an "open FPGA reference" function pointed toward the target will do the job and trigger the data display in the DSM.

 

Many thanks.

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Hello, I am facing the same problem (or one similiar) with RT Targer cRIO-9101. (https://forums.ni.com/t5/LabVIEW/Shared-Variable-quot-No-Known-Value-quot-on-Distributed-System/td-p...)

Can you please explain with more details what you have done?

 

Thanks in Advance

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