When using RSE do I need to connect to both daq terminals?

[davey31415]

 

I am using a USB 6008 with the first analog input set to differential and five others set to reference single ended.

Do I need to use the ground connection when making an RSE measurement?

I ask because according to the connection diagram shown by the express DAQ assistant, the differential input is using pins 2 and 3 while one of the RSE inputs is using pins 3 and 4.  If pin 3 is not at the same potential as ground for the RSE input I expect there would be problems.  Why would this pin be shared in such a way? 

Also, is there a place inside LabVIEW/MAX other than the DAQ assistant where I can view connection diagrams (preferably one with pin numbers)?

Thanks,

Dave

[Dennis_Knutson]

I can't run the DAQ Assistant for the 6008 but according to the manual (which has a pin diagram), you should not be using pin 3 at all for RSE if you specify ai0 as differential. What's your channel list? If it includes ai4, then I would think you would get an error if you try to build the task. Ai4 gets reserved for the differential measurement. The channel list would have to be ai0, ai1, ai2, ai3, ai5, and then ai6.

Message Edited by Dennis Knutson on 03-26-2009 05:25 PM