Device Pinout for the PCI 6225 in Differential AI Mode

[akeister]

Simple question: where is the device pinout for the PCI 6225 for differential analog input mode? I've looked in the Device Pinouts in MAX, in the NI 622x Specifications document, and several other places, but I haven't been able to find it. I've found pinouts for referenced single-ended measurements, but not differential. 

Related question: don't most people use devices like the 6225 for differential analog input? Then why in tarnation do a lot of NI's hardware manuals make you look high and low for the differential input version? 

Thanks!

[akeister]

Is this the correct scheme?

[akeister]

My previous post has been confirmed in the M-series User Manual, (Adobe) page 34. However, this is still not as good as a pinout. For example, what am I supposed to call the channels in LabVIEW? I know what they're supposed to be from experience, but someone who hasn't seen this before would be lost.

So my second question in the OP remains unanswered: why doesn't NI just post a pinout for each connection type?

[Dennis_Knutson]

The diagrams are available to new users. Below is what you see in the DAQ Assistant.

What you are supposed to call the channels is ai0, ai1, etc. Referring to pins numbers would make it impossible to use the same code when you change DAQ boards.

[akeister · Accepted solution]

"Referring to pins numbers would make it impossible to use the same code when you change DAQ boards."

I'm not quite sure I follow here. Can you please expound a bit further? Are you referring to Pins 1-68 on Connector 0 and Pins 1-68 on Connector 1? If so, I'm not sure I follow. A different pinout doesn't necessarily change code. If I were to replace a 6225 with some other equivalent DAQmx device with at least as many channels, and the device number was the same, then I wouldn't have to change any channel names in the code, would I? It would definitely change the wiring, which is precisely what I'm doing right now.

I know that analog input channels look like ai0, ai1, etc. My concern is later on: where do the skips happen when you're in differential mode? 

I've attached exactly what I would like to see in the documentation of ANY analog input device that admits the differential mode, only with the + and - channel names only and not the AI0-AI79 labels. I could not find this picture anywhere, but instead had to laboriously compute this pinout. If you know where to find this picture, I'd be most grateful.

Thanks for replying. 

[Dennis_Knutson]

Sorry, thought you were asking for the ability to specify a pin number instead of name.

Since I know that I just have to add 8 to the first channel of a differential pair, I don't really miss the notation but I would recomend you make the suggestion to the DAQ Idea Exchange.