This window lets you view the joystick input coming from the Pinscape Controller unit. This shows the processed version of the KL25Z input, in the format seen by Visual Pinball and other software when reading from the joystick.
The accelerometer input should automatically zero itself after about ten seconds if you let the KL25Z sit still. You never have to calibrate it manually, since it zeroes itself in its current position any time it's stationary for a while.
The plunger readings shown here take into account the calibration. If the plunger is calibrated properly, the reading should be at the zero point, indicated by the arrow, when the physical plunger is "parked" at its normal resting position. The bar should move to the right when you pull back the plunger. If the reading isn't showing zero when the plunger is at its resting position, you should re-run the calibration process from the Plunger Setup window.
The buttons displayed here are the "mapped" joystick buttons. These aren't exactly the same as the physical buttons wired to the controller, because the firmware translates each button press to the mapping you selected for the button, either as a joystick button or a keyboard key. If you assigned a physical button as a keyboard key, it won't show up here at all when you press it, because the button sends input to Windows as keyboard input instead. If you mapped a physical button to a joystick button, the assigned button should light up here when you press it.
If you're still setting up your connections, you might find it helpful to look at the Button Tester and Plunger Tester windows. Those will give you a more direct view of what's going on at the hardware level.
The "Capture" option lets you collect readings from the accelerometer and plunger inputs and save the collected data to a file. This is mostly for debugging purposes. When the capture section is enabled, hold down the Control key to collect data. The new readings are added to the text box. (Readings are only collected while you're holding down the Control key to avoid collecting excessive amounts - the readings come in very fast. When troubleshooting, you usually only want to collect readings related to something specific you're doing, like firing the plunger or nudging the machine. Filtering with the Control key makes it fairly easy to collect a focused set of readings around a particular event.) Once you've collected the readings you're after, you can save them to a file if desired by clicking the disk icon. This can be helpful for sharing the data with someone else who's helping you troubleshoot.