Hello Gearoid,
The best place to start would be the instrument driver network:
http://zone.ni.com/idnet97.nsf/browse/
In most instrument drivers there should be some kind of calibration _.vi. With these routines you should be able to set up your calibration program.
If the instrument driver is not available or does not contain a calibration _.vi, then you would have to get the low level function that will call the calibration feature of your instrument from the instruments user manual.
I hope this helps, Thank you,
Doug