PETRO-METER SERIES 2700
FUEL DEVIL
WIRELESS TANK GAUGE

The heart of the Petro-Meter Series 2700 Fuel Devil design is a ratiometric* oscillator. It obtains level readings based on the proportional capacitance of the fuel covering the inner surface of the probe’s outer tube, and outer surface of the probe’s inner tube. This inner-outer inter-tube space creates the plates of a capacitor. The value of
this capacitance is directly proportional to the dielectric of the material between the two surfaces. The dielectric of most gasses is approximately 1 (i.e. air or fuel vapor). The dielectric of liquid fuel oil is a small fraction over 2. Therefore, the difference between the capacitance of an empty probe and a full probe is 100%, making it easy to read accurately - if you know what you’re doing.

*Ratiometric: This is the type and quality of the analog-to-digital conversion oscillator method being used. This type of conversion method assures that the system remains proportionally accurate due to its internal laser trimmed components, even when the battery voltage begins to drop over time as it discharges. This of course,
until the battery warning goes off indicating that the transmitter needs new batteries. The ratiometric analog-to- digital converter will allow the system to operate accurately long after the low battery warning goes off to insure that correct data will be sent to the receiver.

Safety: Capacitive fuel probes have been, in one form or other, used on commercial and military aircraft effectively for more than 50 years. The Series 2700 Fuel Devil is the first device of its class developed exclusively for use with common heating fuels. Credit for this ingenious adaptation in fact goes to the same mind that has engineered the world’s first microprocessor controlled capacitive fuel gauge system for a commercial aircraft; the McDonnell-Douglas DC9-80. This level detecting principle has flown flawlessly in this aircraft since 1979, and since has proliferated into numerous other commercial and military aircraft to this day.

The Fuel Devil’s CMOS* analog-to-digital converter attaches to the capacitive probe and consumes only 1/1000 of a Watt of power. The actual current flowing through the capacitive probe is approximately 2 Microamperes, or 2 One Millionths of an ampere for approximately 10 Microwatts of power. For perspective, if you were to make a cell
phone call in the vicinity of your fuel tank, you would effectively expose the tank contents to a power field in the range of 100 Milliwatts; in other words 10,000 times greater than the Fuel Devil.

FCC Data: The Fuel Devil transmits in ranges between 418 and 433MHz at a power level of less than 10 Milliwatts. FCC regulations dictate that devices within its class (i.e. garage door openers) must transmit for less than 5 seconds every 5 minutes. In effect, the Series 2700 Fuel Devil abides to FCC rules and regulations for power and duration within the allotted frequency spectrum.
*CMOS (Complementary Metal–Oxide–Semiconductor).

PETRO-METER CORPORATION – 300 WEST HOFFMAN AVENUE – LINDENHURST, NY 11757
TF 800.935.8257 – PH 631.225.2322 – FX 631.225.2522 – www.petro-meter.com