Chapter 2 System Description - Garnet SeeLevel I 705 Series Manual

CHAPTER 2
SYSTEM DESCRIPTION
The SeeLeveL consists of a display unit that mounts inside the RV, and
sender panels that stick to the side of the holding tank. A single two
conductor wire is used to connect all the sender panels to the display.
The Sender: Each sender panel is a flexible self adhesive printed circuit
board which is stuck to the side of the holding tank. The sender panel can be
cut to length to match the height of the tank, and it auto calibrates itself so that
it can read from Empty to Full regardless of the height of the tank. The sender
scans the water level through the tank wall using patented digital techniques
programmed into the sender microprocessor. When the sender transmits the
water level information to the display, it sends a digital code that has built in
error detection, making it impossible for the display to read an incorrect level,
even if the wiring is bad. In addition to the level, the sender also transmits
diagnostic information about its operation. This information can be used to
determine if there is buildup of sludge on the inside of the tank, or to
determine if the sender is delaminating from the side of the tank. If sludge
buildup in the tank becomes extreme the gauge will cease to operate (the tank
will always read empty), so by monitoring the signal level the tank can be
cleaned before the buildup gets excessive. Various sender options are
available to monitor tanks from 4 inches to 24 inches tall.
The Display: The display receives the information from the three sender
panels via a single two conductor wire, and displays the level information in
percent of full on a five segment LED bar graph. When the front panel button
for a particular tank is pressed, the display powers up and displays the level
for that tank. If the button is pressed and released, the display will show the
level for about 5 seconds and then shut down automatically. If another button
is pressed before the display shuts down, then the new level will immediately
be shown. If the same button is pressed twice, the display will hold on that
tank and continue to show updated levels for 5 minutes before shutting off.
This allows the user to monitor the filling or draining of a tank. By pressing
two buttons at once, the diagnostic functions can be accessed, these are
described in detail in the troubleshooting chapter.
If a sender is operating properly and connected to the display with good
wiring, then the display will show the level normally. If the wiring is
disconnected, shorted, or cut, or if the sender panel is defective, then the