4-66.2. TANK LEVEL INDICATION - TRANSMITTER - MAINTENANCE INSTRUCTIONS (Continued).
(3) As the fluid level in the tank that houses the transmitter moves up and down, the float moves up and
down. Bar magnets in the float operate tap switches in a two-at-a-time, three-at-a-time, two-at-a-time sequence
as the float moves. When two adjacent tap switches are closed, the effective electrical tap point on the voltage
divider network is halfway between the two switches. As the magnetic float closes the next tap switch (with the
first two remaining in the closed position), the effective tap point is halfway between the first and third tap
switches; that is, at the middle switch of the three. This middle point is one-half inch from the effective tap
point established when only two tap switches were closed. As a result, voltage drops are read in half-inch
increments of float travel.