600x's don't have "calibration" constants, have to bump up to the 621x to get that.
The input/output levels are in the specifications. I developed a verification system for the 600x using a traceable power supply/DMM to do a check on the functionality of the 6008's we use on production for ISO certification. If it fails, we toss it and replace the DAQ.
Frequency will depend on your use, yearly is generally accepted. More critical devices or devices that tend to drift I choose to cal more often.
I'm using a USB-6361, which has a recommended calibration interval of 2 years, however it wasn't shipped with any calibration certificates. Is 2 years from the date of first use okay?
If you go into MAX and select the board under devices. There should be a tab on the bottom that says calibration and gives you some information the last external and self calibration.
