Because, I think, most cal labs have a guarantee on their calibration - i.e., the instrument will stay within cal for the specified period because they performed the cal according to the manufacturer's specs. If they are not familiar with the manufacturer, they would likely not be willing to provide such a guarantee. Add to that the fact that they usually are so familiar with the cal procedure for common instruments that they do not need to perform special set-up for each one - they probably have their equipment pre-programmed with stored settings for all the common instrument models. A homebrew instrument would complicate their procedure and it may not be worth the added effort to them financially. Sean On Sat, Nov 16, 2013 at 7:19 AM, Nicola Perotto wr= ote: > Hi, > > On 16/11/2013 04:45, Sean Breheny wrote: > > I don't even know if a typical cal lab would be willing to > > perform calibration on a custom instrument. > > > Why not?! It's a service you pay for. > I used to calibrate some custom datalogger (in Italy) without any problem= .. > N > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .