NRuff,
Thanks for contacting National Instruments. The USB M-Series are not currently supported in Calibration Executive. You should be able to use the
calibration instructions for the USB-6251 to calibrate it, or you can send it in and we will calibrate it for a fee.
Let me know if you have any further questions
Regards.
Kenn North
Principal Product Manager - Search, Digital Analytics
http://ni.com/search