Capacitive fuel level with accelerometer GPSM Pro Sensor. Used for precise measurements of liquids (gas, diesel, water, etc). I has inbuild accelerometer that provide adoptive level readings during stop and movement of a vehicle.

1. USER GUIDE
FUEL LEVEL SENSOR
GPSM
PRO SENSOR
Intelli LLC
Ukraine, 03035, Kyiv, Lva Tolstogo street, 63
tel.: +38 (044) 3622956
fax: +38 (044) 2494445
E-mail: info@fuel-sensor.com
www.fuel-sensor.com www.intelli.com.ua
Revision: 5.03
Enable 3D View

2. Contents
1. Fuel level sensor application.........................................................................................................3
2. Specifications ................................................................................................................................3
3. General view .................................................................................................................................5
3.1. Dimensions ............................................................................................................................5
3.2. Description of connector pins ...............................................................................................5
4. Wiring diagram to connect the power supply and control module .............................................6
4.1. Diagram of wiring through the battery disconnect switch ...................................................7
4.2. Diagram of avoiding the battery disconnect switch..............................................................7
5. The GPSM Pro Sensor installation and calibration .......................................................................7
5.1. Installation procedure ...........................................................................................................9
5.2. Tank tare..............................................................................................................................10
6. Operation concept ......................................................................................................................10
7. Operating rules ...........................................................................................................................10
8. Component parts ........................................................................................................................10
9. Servicing......................................................................................................................................11
10. Repair ......................................................................................................................................11
11. Warranty .................................................................................................................................11
Attachment А. The unit calibration guide

3. 1. Fuel level sensor application
GPSM Pro Sensor is applied for measuring the level of fuel and lubrication materials (like diesel
oil, petrol, paraffin oil) and other dielectric liquids keeping its physical character at the operating
temperature range.
The given manual describes the operation and setting of GPSM Pro Sensor, hereafter referred
to as “sensor”, in conjunction with the fuel metering systems.
Observe job safety rules before installation of the fuel level sensor!
2. Specifications
Electrical specification
DC supply voltage, V 9 - 30
Input current (at 12V), mA max 50
Serial interface RS-485, RS-232 (optionally)
ADC bit capacity 12
Level gauging
Bit rate, Mbit/s 1200, 2400, 4800, 9600,
19200, 38400, 57600, 115200
Averaging time, s 0 - 100
Automatic data output interval, s 0 - 255
Measuring period, s 1
e erat re eas r n ran e, С - 80 … + 80
Computer controlled accelerometer calibration yes
Liquids to be measured
Fuels petrol, diesel oil, paraffin oil
Oils Engine oils, transmission lubricants, power
steering fluids and hydraulic oils
Bio fuel Ethanol Е100, Е85, Е50, Е20, Е10, ethanol
Range Accuracy
Rate of ambient temperature change
-20 С…+80 С, %
ax ±0,7
Rate of ambient temperature change
-80 …+80 С, %
ax ±0,9
Operation conditions
IP Code IP 67
erat n te erat re, С -80…+80
EMC Immunity Level SAE J1113/2 1996
Figure 1 shows the straight-line relation between the fuel level and sensing data. Figure 2 provides
data about relation between accuracy and temperature.
Figure 3 shows volume and temperature relationship of a fuel. For demonstration purposes, this
relationship showed for diesel oil with average density.

4. Fig. 1. Metrological characteristics of the fuel level sensor.
Fig. 2. Constancy of Pro Sensor fuel gauge unit readings at -60 °С… +80 °С temperature range.
Fig. 3. Relation between diesel fuel volume and temperature. Average density of the diesel fuel
(810kg/m3) at 20 °С.
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Unitreadings
Fuel level
Relation between fuel level and output data
0,0%
0,1%
0,2%
0,3%
0,4%
0,5%
0,6%
0,7%
-60 -40 -20 0 20 40 60 80
Additionalpercentageerror,%
Temperature, °С
Relation between accuracy of the fuel level sensing and
temperature of the environment
1,149
1,169
1,189
1,209
1,229
1,249
1,269
1,289
-60 -40 -20 0 20 40 60 80
Specificvolume,l/kg
Temperature, °С
Relation of fuel level and temperature

5. 3. General view
3.1. Dimensions
33мм
67мм
25мм
L
1
2
3
4 5мм
67мм
330±100мм
5
http://fuel-sensor.com
Fig. 4. General view, mounting dimensions of the Pro Sensor.
1 - he eas r n art of the n t has a len th of 200…6000 and cons sts of two arallel aluminum
tubes having anodized coating.
2 - The case made of high-strength polymer.
3 - Flexible protection tube.
4 - Four-pin connector.
5 - Fixing holes.
Due to the commonly used location of holes, the unit can easily be mounted instead of the regular
(float sensors) fuel gauge units.
3.2. Description of connector pins
A – + 9-30 V
B – B (RS-485)
C – GND (-)
D – A (RS-485)
Fig. 5. The layout of the connector pins of Pro Sensor unit.

6. red/green
yellow
blue
black/brown
Fig. 6. The layout of the pins of Pro Sensor fuel gauge unit.
А – yellow;
В – blue;
«+» – red/green;
GND («-») – blackbrown.
The Pro Sensor is protected against polarity reversal; the protection against polarity reversal
will protect the electronics from incorrect connection of the voltage. RS-485 circuits are
protected from overvoltage (up to 30V) and short circuit.
The improper connection of the unit results in termination of the warranty liabilities of the unit
supplier.
Regardless the unit modification, it is prohibited to connect the unit to the in vehicle network
without installing two additional fuses for “+” and “-” that come with the unit. The fuses should
have a capacity less than 500 mA.
4. Wiring diagram to connect the power supply and control module
There are two recommended schemes to connect the power supply:
1) Connection to the power of the vehicle with the battery disconnect switch.
2) Connection to the power supply avoiding the battery disconnect switch.
Pro Sensor has a galvanic isolation (1000 V) between its electric circuits.
Besides, the unit polymeric case is isolated from the car body. That is why the Pro Sensor can be
connected directly to the car battery avoiding the battery cut off switch.

7. 4.1. Diagram of wiring through the battery disconnect switch
Vehicle
battery
Fleet
management
terminal
RS485 A
RS485 B
Battery
disconnect
switch GPSM Pro sensor with
built-in galvanic isolation
F1F2
F3
Vehicle electrical
system
The unit case
has electric
isolation from
the car
disconnect
switch
Fig. 7. Connection diagram №1. Connecting the unit to the power source through the battery
disconnect switch.
4.2. Diagram of avoiding the battery disconnect switch
Vehicle
battery
Fleet
management
terminal
RS485 A
RS485 B
Battery
disconnect
switch GPSM Pro sensor with
built-in galvanic isolation
F1 F2
F3
Vehicle electrical
system
The unit case
has electric
isolation from
the car
disconnect
switch
Fig. 8. Connection diagram №2. Connecting the unit to the power source directly to the vehicle’s
battery.
5. The GPSM Pro Sensor installation and calibration
It is recommended to install the fuel level sensor in geometric center of the fuel tank. It helps
to reduce error in measurement when the vehicle is inclined. If it is needed to install two sensors

8. in one tank, they should be placed in one diagonal line. Examples of the proper sensor mounting
are given below:
Fig. 9. Tank, side view. Recommended installation place.
It is recommended to install two units in a tank to reduce the measurement uncertainty when
the vehicle is inclined or if the tank length exceed 1.2 meters.
68%
32%
50% 50% 32%
68%
32%+68%
2
50%
68%+32%
2
50%
Fig. 10. Tank, side view. Installation of two sensors in one tank.
Place the fuel level sensor as close
to the tank geometric center
as possible.
If two sensors installed into one tank, they should be
placed on one diagonal line.
GPSM
GPSM
GPSM
Fig. 11. Tank, top view. Recommended positions for installation of one or two Pro Sensor units.

9. 5.1. Installation procedure
It is required to remove the tank, fill it with water and/or evaporate residual fuel before
starting the unit installation! It also refers to all tanks containing flammable liquids.
Dealing with diesel fuel tanks, it is required to get rid of the fuel steams to avoid the explosion!
1. Having finished the steaming, drill a small hole on the unit would-be location. Take a rod
and check for the absence of blocks like bumps/dimples in a tank bottom or a baffle.
2. Make a hole in a tank (35-40mm) with a crown milling cutter or dual-cut drill.
3. Measure the tank height and cut the unit making it 10-200 mm shorter than a tank.
20 мм
L, мм
Fig. 12. Choosing the Pro Sensor unit length.
4. Remove the cutting burrs from the unit tubes.
5. Try the unit on a tank and mark the positions for drilling the holes for five self-tapping
screws.
6. Drill the holes for self-tapping screws.
7. Perform the unit calibration testing (see Attachment A)
8. Install the unit with a sealing; screw the self-tapping screws supplied as a set tightening
every next screw located opposite.
Fig.13. The sequence of tightening the self-tapping screws while installing the Pro Sensor fuel
gauge unit.

10. 9. Enable the unit to the extending cable by connecting the pins, after putting two additional
fuses for “+” and “-” of the in vehicle network.
5.2. Tank tare
Calibration test means obtaining a table of correspondence of the unit output signal (in
nominal units) to the fuel volume.
1. Before starting calibration, put the vehicle on the level ground.
2. Drain the fuel from the tank.
3. Fuel until the unit readings start changing. Write the unit readings and the used fuel
volume into a Table.
4. Fill the tank with 10-40 liters of fuel at a blow (depending on the tank volume) and each
time write the output signal values and the corresponding amount of fuel into a Table.
6. Operation concept
The unit uses the capacity method of measuring the liquid level, which is based on the
dependence of capacity of condenser from dielectric capacitance of the medium between its
plates.
For the operational comfort, Pro Sensor unit has a built-in LED having two operation modes:
1) Flashing at the unit acceleration and tank vibration;
2) Flashing at transferring the data to an external device.
You can switch the LED off at the settings of the unit profile program.
7. Operating rules
The unit operating rules:
- it is prohibited to expose the unit to aggressive influences, magnetic fields having the
activity exceeding the one specified in SAE J1113/2 1996, mechanical stresses, sudden
alteration of temperatures differing from the natural ones, also to operate the unit under
conditions differing from conditions described in this manual;
- it is prohibited to connect the unit to devices having interface differing from the one
described in this manual;
- the installation and setting of the unit should be performed by the staff who has studied
the occupation standards, the unit operation concept, its operating features and technical
specification.
8. Component parts
The supply package includes:
- Pro Sensor fuel gauge unit;
- extension cable (up to 8 m);
- rubber pad;

11. - self-tapping screws (5 pcs) fastening the unit to a tank;
- a fuse for a fuel gauge unit;
- a device for setting the fuel gauge unit (optional);
9. Servicing
The unit does not require servicing.
10. Repair
The unit is maintainable if there is no mechanical damage.
11. Warranty
Warranty period is 24 months since production date. The production date can be seen in the
unit datasheet.
Removing the device number from the unit leads to the cessation of the warranty.
The manufacturer guarantees the normal operation of the unit if the customer follows the
operating rules.