NI9269 Increasing Output Voltage Range - operations on Labview FPGA

[fromano83]

Hello,

I was looking for an example of a vi with the right way to assign a value  to an NI board, which has two  cascaded channels (in order to increase its output range).

I'm working with a NI-CRIO 9082, for a real-time testing application.

I need  to provide on channel a signal that can vary among +/-15V, so for this purpose I equip the CRIO with a output board: NI9269, which allows increasing a channel output range up to 40V (according the datasheet) by cascading the 4 channels.
From the datasheet of the board NI9269 (see first figure) I found the hardwire way to cascade two channels to reach up 20V.

But for what concerns the logic to implement on the FPGA (from a Labview point of view),  I was wondering in order to provide 15V

- Should I assign the final value to the first channel  (AO0- see second figure) ?

- Or should I assign half of the value to the first channel (7.5V on AO0) and  the other half on the second channel (7.5V on AO1) in order to obtain 15V as output?

thank you 

[.imb · Accepted solution]

Hello Fromano,

I would try your second suggestion, and assign each channel half of the signal. I guess you did not change any parameter within the project to tell the module that its outputs are cascaded, so I would not expect a command to AO0 to have an effect on AO1.

A way to know for sure would be to try it and measure the generated voltage.

[GerdW · Accepted solution]

Hi fromano,

should I assign half of the value to the first channel (7.5V on AO0) and  the other half on the second channel (7.5V on AO1) in order to obtain 15V as output?

This would be easiest.

You can also assign 10V to AO0 and 5V to AO1 (or any other ratio you like) - that depends on your preferences. 😄

[fromano83]

thank you