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Using BNC-2120 to blink LEDs



I have the BNC 2120 connected to slot two of a NI PXIe-6361. Trying to use the BNC to blink two LED at a frequency of 10 Hz but I am not sure where to connect the wire (In P0.0 and P0.1 of the Digital I/0 section or in P2.0 and P2.1 of the Timing I/0 section.)


When I connect it in the Digital I/0 section I get the error: Selected lines do not support buffered operations.


Not sure why I am getting this error.


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The ultimate goal of this project is to have the two LEDs blinking at 10Hz alternatively. Meaning while one is on the other is off.

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Hi Ucon20,


The LEDs on your BNC-2120 board are connected to port 0 on your NI PXIe-6361 card. Therefore, to make those lights blink, you need to 

send a boolean value to any of the 8 lines on port 0. For example, to light up the LED at the bottom of your BNC-2120 you need to send a "1" to

P0.0. To do this, you can use the following LabVIEW shipping example:

[LabVIEW] -> Help -> Find Examples -> Hardware Input and Output -> DAQmx ->Digital Generation -> Write Dig

And alternative version of this example can be found here.

After running the aboved mentionned example, are you able to turn on/off the LEDs on your BNC board with controls in LabVIEW?

Now, I am not sure exactly how you are trying to activate those DIO lines (posting you code here might be helpful), but one of the reasons that you are getting "Selected lines do not support buffered operations" might be because you are trying to do a clocked DIO Waveform output operation on that line.


Also, here is helpful video to get you started with using counters and DIO lines:

Using Counters and Digital I/O



RF Toolkits, Product Support Engineer
National Instruments
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On a PXIe-6361 (and all other X Series devices), digital port 0 is the only port that can do buffered operations (timed digital). Ports 1 and 2 (which are shared with PFI lines) can only be used for static digital.


You should not need to connect any wires to use the LEDs on the BNC-2120 as outputs. (If you wanted to connect another device, such a sensor, and do digital input or output to it, then you would use the terminal connectors.)


For a demonstration, disconnect all wires from the 'Digital I/O' section, then open the MAX Test Panels for the PXIe-6361, go to the 'Digital I/O' section, set port0/line0:7 to outputs, then start the task and play with the 'Select State' switches.

Brandon Streiff ·
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