How to use the eclipse arduino scope?
The simplot library (referenced below) is an excellent example of how to use the scope which works as advertised.
Firstly, readers should note that there are two different Arduino plugins for Eclipse ("Eclipse C++ IDE for Arduino" and "Arduino Eclipse plugin named Sloeber V3"). Only the latter has a scope and a seriel monitor that allows data to be sent.
Getting simplot and the scope to work, however, can be a problem depending on the platform. On a Mac, with the latest version of Eclipse (Neon.2 Release Candidate 2) and the Sloeber V3 plugin, the default path to the Private Library is Users/yourname/Arduino/libraries. Unfortunately, this path doesn't (necessarily) exist. 
One could spend hours trying to figure out how and where to import a library when the critical library folder doesn't exist.

The solution (at least on a Mac):


Create a folder (arbitraily) named "Users/yourname/Eclipse/libraries". 
Include this folder in Eclipse - Preferences - Arduino - Private Library Path
Download jantje's entire Github Arduino Library, unpack it and move the "simplot" folder into your Private Library Folder. "simplot" should now show up in the libraries.
Use: Arduino - Add a Library to the Selected Project 
Or build a project using the simplot.ino example.


It should work beautifully.