A rudder angle indicator displays the angle of the rudder or rudders.
Senders
SD0041 90530 SENDER (Rudder Angle) (SINGLE station) (Standard or Floating ground)
SD0039 90531 SENDER (Rudder Angle) (SINGLE station) (Standard or Floating ground)
The senders work by measuring the angle of the rudder or rudders and converting that to a level, where 180 ohms equals starboard, 95 ohms is the mid point, and 10 ohms displays port on the rudder indicator.