I am using 16.6 and have the diff pairs correctly assigned. I have constraints set up for the Dynamic Phase tolerance for both the Max Length and the tolerance. The tool however doesn't appear to actually be doing the checking. If I load the db in 17.2, the error shows up in the constraint manager. It doesn't show up in 16.6. Does Dynamic Phase not work in 16.6?
Depends on the version of software you are running. When Dynamic Phase was introduced initially at 16.6 you would have needed Allegro PCB Designer + High Speed license. Now it is available in OrCAD PCB Professional 17.2 so what level of tools do you have?
16.6 with the high speed and miniturization.
OK so the license is good enough to be able to run this. What exact version of 16.6 ae you running? If it's 16.6 pXXX then get the latest hotfix from http://support.cadence.com and try again. If you have 16.6 SXXX then make sure under Setup - Constraints - Modes - Electrical Modes that all differential pair checks are enabled.