The POTAR is a 10 KOhms potentiometer which is attached to the plunger (ball lance) and which allows you to simulate the latter in your Pincab.
To connect it to KL SHIELD or to your KL25Z, you have at your disposal a socket with 4 connectors.
The GND connects to the GND of your KL SHIELD or your KL25Z
The 3.3V connects to the + 3.3V of your KL SHIELD or your KL25Z
the PLUNGER connects to the B0-PLUNGER terminal of the KL SHIELD or the preset input of your KL25Z
The LB (Launch Ball) connects to the terminal of the Launch Ball button of your KL SHIELD (if you use the basic configurations, it will be on BT5) if you use a Launch Ball button
The Launch Ball connector at the end of the POTAR is connected to the LB and GND terminals of the main socket.
This connection is used to connect a Launch Ball button above. Either you use a button at the end of your POTAR, plug its 2 pins on it, or even if you use a Launch Ball button below your ball lance, nothing prevents you from plugging the latter above for a cleaner wiring.
Once your POTAR is installed, don’t forget to declare it in pinscape config using one of the KL SHIELD configuration files, and don’t forget to calibrate it using the CALIBER card, or with the Pinscape Config software Tool.
maoul59 concocted an STL file (with the source available in SKP) to mount the POTAR on a Williams / Stern type Plunger : download it here