LabVIEW with Keithley 6485 picoammeter and 2410 SMU

Hi all,

 I am having an issue with the "zchk" (zero check) on the front panel of the Keithley 6485 picoammeter-I need zchk to be turned off, and I can manually do this, but when I run the labview program, it automatically turns it on and I don't recieve any results. Where could I turn off zchk in labview? I've looked through the driver, and configure measurement or configure dc current was of no assistance.  

Using:

GPIB-USB-HS

Labview 2009/Windows

Drivers: 

http://www.tek.com/specialty-instruments/6485-software/models-6485-6487-and-6514-ivi-visa-based-driver-visual-basic-vb-

http://sine.ni.com/apps/utf8/niid_web_display.download_page?p_id_guid=25B255F3AA83660EE0440003BA7CCD71