TLM150 User’s Manual
Page 4
Revision 1.2
•
The sensor component of the TLM150 must be mounted over the deepest part of
the tank, in order to obtain accurate depth readings when the tank is empty or
near empty.
•
In order to obtain accurate readings when the tank is empty, the tank bottom
directly under the TLM150 must be both smooth and flat, so that the ultrasonic
sound waves transmitted by the sender are reflected back to the sender for
measurement. If the tank bottom under the TLM150 is sloped, grooved, or rough,
then the TLM150 may not report an accurate level reading (or any level reading
at all) when the tank is empty.
•
The area below the sensor component of the TLM150 must be free of obstruction
from tank baffles or return lines that might reflect ultrasonic waves back towards
the sensor component, causing inaccurate depth readings.
•
The sensor component of the TLM150 must be mounted away from the tank
walls, so that reflections from the tank walls do not cause inaccurate depth
readings.
•
For a flat bottom tank, the mounting hole in the top of the tank through which the
TLM150 measures fluid level should be located as close to the center of the tank,
both front-to-back and side-to-side, as possible. This will ensure maximum
accuracy of reading in the event that the vessel experiences pitch and roll.
2.3.1 Effect of Pitch and Roll on the TLM150
Assuming that the TLM150 sensor component is mounted on a flat tank top, the TLM150 will
operate correctly as long as the vessel does not experience pitch and/or roll in excess of 6° for
an extended period of time. This can occur on a sailboat when the boat is heeled over, or on a
powerboat with a non-displacement (planing) hull. Temporary pitch and roll due to wave
motion and will not adversely affect tank level readings.
If you are in a sailing vessel or a powerboat with a non-displacement hull and will experience
pitch and/or roll in excess of 6° for an extended period of time, you can install a Non-
Displacement Hull Focus Tube below the sensor (please refer to Section 1.5 on page 2 for
ordering information). This is a tube which mounts into the tank before the sensor and directs
the ultrasonic waves down to the surface of the liquid and back. With a focus tube, the
TLM150 will operate correctly as long as the vessel does not exceed 15° of pitch and/or roll for
extended periods of time.
2.4 Mounting the TLM150
2.4.1 Mounting the TLM150 Sensor Component
The TLM150 comes from the factory ready to mount on a tank with the standard SAE J1810 5-
Hole mounting pattern. Maretron offers adapters to allow mounting the TLM150 on a tank with
a 1.5” NPT connection or a 1.25” BSP connection.
