Hi Alex,
Thank you for your post regarding acquiring data from both your Agilent DMM and your NI DAQ card. Having reviewed your code it seems that you have placed a second larger While loop surrounding the entire DMM configuration and setup process, this will reduce the efficiency of your LabVIEW setup as the configration steps only need to be performed once whilst data is continuously read from the DMM during the "Read Measurement" While loop.
LabVIEW can run While loops in parallel to one another, can I suggest you try removing the larger While loop and place your DAQ task in a second seperate While loop. In order to correctly stop both While loop tasks right-click the stop button in the DMM loop and select "Create>>Local Variable" and wire the local variable to the stop condition in your second DAQ while loop, therefore if you press the single stop button both while loops will stop.
Hopefully this assists with your setup Alex, please keep me informed with your progress.
Many Thanks
Jamie S.
Applications Engineer
National Instruments