Thanks Danny,
I fiiiiiinally got some time to play with it last night and I figured it out! (My wife laughs at me every time I tell her I'm playing with my phidget, btw.)
When I get a chance I'll test it out on a PC as well since I'll probably be using an old PC laptop as my roaster host. On a mac anyway it seems that the order in which you start things up is very important. You can't open up the PTS monitoring window on the host before trying to link it to Roastmaster. It puts some sort of a lock on things that prevents the app from picking it up. If that's in the documentation, I skipped right over it. I figured this out after taking your advice and doing the "Support 101 - Have you tried turning it off and on again?" I should know better as I'm in the IT support biz. So I restarted my laptop and iPad, plugged in the PTS, started Roastmaster and voila! I have a linked probe.
I then went back to the Phidget control panel and opened the PTS monitor under the general tab with the web service still running. The probe stayed linked in RM, but nothing showed up in the monitor on the laptop.
The instant I stop the web service and break the link to the RM the sensor appears in the monitor on the laptop.
I then started the web service again. The probe remains unlinked in RM until the instant I close the PTS monitor window on the laptop.
So, I don't know if this is expected behavior or not but it wasn't clear to me when setting it up the first time that I should not have the monitor open on the host while trying to link it to Roastmaster. It also never occurred to me to close the monitor on the host. I guess it can't be monitored in two places at once? Maybe it's not even an option with the Phidget SBC3 which I hope to add to my setup some day.
Anyways, I appreciate your responsiveness and willingness to help. I can't wait to start really putting my phidget to work (wife snickers in the background).
Jon