USB-6008 -1.4 offset

[DAQNewby]

I know this question has been answered before, but I still haven't figured this out.  Here's my problem: I am reading a voltage output from a picoammeter, where the voltage out is proportional to the current being measured.  I have the connection to pin 5&6 (differential mode) and designate differential when I create the task.  Despite this, I am reading an ~-1.4V offset in my signal.  I have read the "kb" that has been posted, but I have designated both in DAQmx and in my VI that this is a differential connection.The most frustrating thing is it was working this afternoon, and after I closed LabVIEW and came back, it no longer worked.  The funny thing is if I leave it connected in differential (pin 5&6, I triple checked) and designate RSE connection, it doesn't give me the offset.  Can someone please help?

[G Lo]

DAQNewby,
 
Could you try measuring differentially on another channel to further troubleshoot the issue?&nbsp; Also, I would suggest looking at table 1 of the <a href="http://zone.ni.com/devzone/cda/tut/p/id/3344" target="_blank">Field Wiring Guide</a>&nbsp;which shows different connections for all configurations.&nbsp; If your source is floating, it is recommended that you utilize resistors in your application.&nbsp; Also, I am not sure which kb you are are referring to but I have included a couple of documents that may provide some further insight into the issue as well.&nbsp; Also, you said that it did not work after you closed LabVIEW.&nbsp; When you reopened your program, did anything get reset to its default value?&nbsp; You can save the configuration on your front panel by selecting Edit&gt;&gt;Make Current Values Default.&nbsp; Hope this helps!
&nbsp;
<a href="http://digital.ni.com/public.nsf/allkb/C7E181E51E4299FC862570A700604141?OpenDocument" target="_blank">6008 Analog Input Circuitry</a>
<a href="http://digital.ni.com/public.nsf/allkb/95CC0CB11D7DF3D18625712E000C4ABD?OpenDocument" target="_blank">6008 Incorrect Readings</a>
<a href="http://digital.ni.com/public.nsf/allkb/E687933C5694AB00862570BD00593CA3?OpenDocument" target="_blank">-1.4V Offset with RSE Connections</a>

[DAQNewby]

Yea, when I use my ai1 to measure a known voltage from a voltage supply it is incorrect, yet when I use ai2 it is correct.&nbsp; I think one of my channels was destroyed when I had an electrostatic discharge in my experiment.&nbsp; Now to keep that from happening again... Thanks for the help,Steve