Just to make the distinction...the blue curve in your screenshot is a control curve. These graph as stair-steps in their own section of the Analyzer, and are meant to correspond to machine control settings, e.g. gas flow, electric current, damper and fan settings, etc. The green curve is a reading curve - these represent (at the moment) just temperature readings. Reading curves can show a Delta (Rate of Rise) curve, while Control curves cannot.
In the Roasting with Roastmaster screencast 5, I've got two Reading curves bound to probes. The green Bean Temp curve, of course, is self-explanatory. The blue curve, though, is a probe in the exhaust vent. That serves as an indicator in my profiles of how I usually work the damper at certain points of a roast. The same things could be achieved with a Control curve, similar to the blue curve in your screenshot - wherein I'd input nodes whenever I change the damper setting. Kind of two different ways in this particular example to accomplish the same thing. I like hands-off roasting, so I don't work with control curves myself.
But, to illustrate how the main curve and its corresponding Delta (Rate of Rise) curve work together, the top green curve in the video is the actual Reading curve consisting of temps - a series of nodes that are read by the probe. The very bottom green curve that's more squiggly is its corresponding Delta (Rate of Rise) curve. It simply shows a graphical and relative value of how quickly the main Reading curve is rising at each point in the roast.
The more data points the curve has, the smoother they both will be. Programatically, I cannot accurately employ any type of graphical curve-smoothing for Reading curves in cases of manual data entry, because that would be guesswork on my part as to how faithful the user is in entering nodes. So, they remain linear from node to node (notice how your green curve looks more like a dot-to-dot drawing). When you get your probes set up, you'll see them smooth out. I'd personally advise shielded (ungrounded) probes - they provide the smoothest transitions in curves. But, either style would word.
In the current version of Roastmaster, you cannot bind a probe to a control curve. That will change soon - lots of expansions are coming in the arena of profiling and data logging. Until then, though, Control curves (the stair-stepped curves) are limited to manual data entry.