NI 9206 Differential Input

[clachankid]

Hello,

I have a NI 9206 card that has 16 differential inputs for some reason inputs 0-7 I can place as differential but inputs 8-16 grey out the differential option in Terminal Configuration. See picture below. Help on this would be greatly appreciated.

[crossrulz]

For differential DAQ channels, AI0 through AI7 are the positive and AI8 through AI15 are the negative.  So, when in differential, AI0 is the difference between AI0 and AI8.  This is why you can't set 8-15 to differential.

[clachankid]

There are a total of 32 inputs so AI0 through AI15 are the positive and AI16 through AI31 are the negative which would give me the 16 differentials. Its card NI 9206.

Thanks

[clachankid]

Sorry I see what your saying now I assume the card was layed out AI0 to AI15 on the positive side and AI16 to AI31 on the negative side, but its actually AI0 to AI7 and AI16 to AI23 on the positive and AI8 to AI15 and AI24 to AI31 on the negative side. Thanks for you help.

[crossrulz]

Yeah, I should have mentioned that the differentials are in sets of 8 pairs.  But it seems that you have it figured out

[tesser2]

On this topic, how can I add all 16 channels to a task. The first 8 channel I can do "ai0:7", but how do I add the second 8?

[GerdW]

Type "ai0:7,ai16:23". Or use the "Browse" option of a DAQmx channel control...

[cpede]

Is it possible to programmable find out if the differential channels are in sets of 8 or not.

It seems that all E-series devices are in sets of 8, and also some USB like the 6218 BNC.

But other devices have another configuration.

I uses c++ and DAQmx but need to see how the differentioal channels are set up.

-cpede

[AirFrantz]

cpede,

I do not know of a way to programmatically determine this.  All of this information is listed in the device specifications that you can find on our website.  You can also determine which physical channels are used in differential mode from NI MAX.  Just right click on the device and select "Device Pinouts".

[cpede]

The reason for asking is, that one of our customers used a PXIe-6358 device, and this did not use blocks of 8, since it has a AI+ and AI- pinouts.

Then again reading http://digital.ni.com/public.nsf/websearch/F672F0B9D9CE739286256723007EB18C?OpenDocument could lead to the understanding that only the E-series devices used this feature. But it seems that also M-series devices uses blocks of 8.

If it cannot be read in the capabilities of the device through DAXmx, is there a rule of thumb to use?

-cpede