Hi Chuck - thanks for the kind words. I'm glad you're learning and enjoying!!
I honestly cannot remember if I've talked much about delta curves in the more recent "Roasting with Roastmaster" videos in the
screencasts library. I know I covered them in the old screencasts, but much has changed in Roastmaster since then.
The basics are this: Roastmaster shows delta curves for every reading curve being displayed in the Analyzer based on the setting in Preferences called Roast Analyzer -> Delta Curves. If that is on, you'll see a delta curve for each reading curve. If it's off, none will be displayed by default.
You can toggle delta curves off and on individually in the Analyzer by two-finger tapping to invoke the Curve list. Long tap on a curve to toggle it to the opposite state., e.g. if the preference setting is On, long-tapping a curve will turn the delta curve off for that curve, and "Delta Off" will be displayed for that curve. The inverse, of course, is true, with "Delta On" being displayed.
I think though, based on your post, that Delta Intervals may be helpful to you. You can define 3 separate delta intervals to track in the Roast Analyzer. Enter the value in seconds that you want reported, e.g. 60 for 1 minute. These three delta values are displayed at the top of the analyzer whenever a reading curve is selected. By default, they report the real-time live values of the probes, accurate to 1/2 second. If you select a node earlier in the curve, though, they report the delta at that moment based on the logged data.
The best workflow to utilize this information, is by constructing your Profiles with "Reference Curves", and using the analyzer in "Profile Targeting Mode". It's easy to see the current Delta information, then tap a close node on a Profile reference curve to see the reference delta information.
I talk about building profiles in Screencast Part 2 and expand on that more in parts 5 and 6.
Let me know if this helps you, or if you have any other questions!