Yes, the Force Copilot calibration process adds the 192g of sensor base mass and adjust the CoG. Base on the precision of the calibration process, it is still possible to obtain estimated payload slithly lower than the sensor mass.
Sorry for the delay! As already pointed out by Mathieu, a good starting point is to clone our official ROS package stack, hosted by ROS-Industrial on Github, to your catkin workspace. Before trying to compile the stack, please also see our ROS wiki page for a short list of dependencies. In the stack, you'll find out there is a specific package for the FT300. Once you "rosrun" the said package, it will start publishing all the FT300's data (i.e. Fx, Fy, Fz, Mx, My & Mz) on specific topics, easily accessible from within your application.
Please don't hesitate to contact me should you have any questions about using our products with ROS. Also, don't hesitate to update me if you have an issue while working on your project and I'll be very happy to provide assistance.
You have to unpack the stream, can’t just convert to a string. The docs on the UR website show you how each packet of the stream has been packed, it’s different depending on the message type. Also, port 30004 is the RTDE port, you have to actually send the setup to the port before it will stream anything back to you. There are good docs on the support site with a python example that we used to base our rtde client on.