Using URL to access resource on cRIO device

[John Lokanis]

I am trying to read and write the digital output on an NI9476 cRIO device in an NI9148 cRIO chassis using the shared variable VIs. I want to create a generic driver that can access any cRIO hardware on the network provided I know the IP, module slot and port on the device I am interested in. I created a simple VI to do this. When I run it, I don't get any errors, but it does not appear to control the output I am targeting. Has anyone else done something simular? Is there something simple I am missing? This is the first time I have messed with cRIO. All our current setups use cFP but we are interested in changing to cRIO hardware in the future.

Here is my code:

thanks for any ideas!

-John

Edited May 4, 2011 by John Lokanis

[TobyD]

I am trying to read and write the digital output on an NI9476 cRIO device in an NI9148 cRIO chassis using the shared variable VIs. I want to create a generic driver that can access any cRIO hardware on the network provided I know the IP, module slot and port on the device I am interested in. I created a simple VI to do this. When I run it, I don't get any errors, but it does not appear to control the output I am targeting. Has anyone else done something simular? Is there something simple I am missing? This is the first time I have messed with cRIO. All our current setups use cFP but we are interested in changing to cRIO hardware in the future.

Here is my code:

thanks for any ideas!

-John

This is off the top of my head as I don't have LV in front of me, but I think your URL might need to be set to ni.var.io:// instead of ni.var.psp:// when configuring outputs.

-Toby

[John Lokanis]

ni.var.io allows forcing outputs via property nodes but does not allow them to be read back. The shared variable VI reject a URL that uses ni.var.io. They accept ni.var.psp. Also, you cannot browse for anything under ni.var.io.

Looks like it is time to call in the big guns at NI.

BTW: I was able to get it to work somewhat by adding a 300ms delay after the write and adding a delay before the close. But, the value does not 'stick' in the DO. Once the close is called, the value reverts to false (off). If I remove the close, the value reverts when the VI stops. No idea why it wold 'latch' the value.