SEE MORE OF INFORMATION ON WWW.STRELA-FLS.COM   Fuel level sensors STRELA are used for petroleum, oil and lubricants.  They have wide application in automotive telematic systems for fuel level recording such as Intellitrac, GoSafe, Enfora, Teltonika and others. Various interfaces provide a suitable solution for all telematic systems.

 DESCRIPTION 

There are different kinds of output signal that’s why we’ve created different types of sensors. You can choose among:

·  Analog output (0-5 V, 0-7V,0-10V) – Strela A

·  Frequency output (500-1500 Hz) – Strela F

·  Digital output (serial RS232 of 485 interface with 1024 or 4096 points resolution) – Strela D232, Strela D485

·  Custom interfaces by demand: current 4-20 mA, MODBUS.

*Is correct for sensors, which are calibrated (recommend) after reducing of length, without calibration is acceptable reducing of length 

of Strela A and Strela F sensors no more as to 50% of initial length, in such case the output value range min and max shifts.
** Are available variants with 0-5V output and for vehicles with 12V on-board voltage 0-7V output.

Electronic components of sensor are immersed into elastic compound that provides maximum protection (IP66) and safety under any operation conditions.

Measuring tubes are made of the material that doesn’t react with fuel components.

Sensors are adjustable for desired tank height so you may cut them according to the height of your tank. But from fuel lever sensors (FLS for short) Strela A and Strela F you may not cut more than 50% of initial length without calibration.

All the sensors can be cut for any height with the additional calibration.

There is a list of available initial length of sensors: 250, 350, 500, 700, 1000, 1400, 2000 mm. You should choose from this list the most suitable length for your need; however take the longer one to provide the most accurate length.

Sensors have built-in supply voltage stabilizer and sensor output doesn’t depend from onboard voltage.

Advantages:

- Possibility of calibration of all types of "Strela" sensors.
- Electric insulation of head of sensor from the tank.
- The output range of D232/485 sensors is adjustable to 1023 or 4096 points to sensors length.
- Possibility to set the tank calibration table (tare table) into sensors memory, that allows to get exactly the volume sensor.
- Possibility to use termocompensation and self-diagnostic codes.
- Protection from polarity reversal and short connection of outputs wire to ground

(in some models from short connection of output to "+" too).

- Internal averaging of fuel data.

- Possibility to record of calibration curve (level - volume) in sensor, so it becomes fuel volume sensor
- Availability of summator-devices that allow to sum signals from 2-4 of freqyently output sensors and send the sum data

to GPS-device using voltage, frequency or RS232 interface.
- Length up to 4000mm, availability of the split-design sensors (from basic 1000 or 1500 mm part and one or more additional parts of necessary length).

We can help you to receive good fuel data from ANY AVL device!

Frequently asked questions

What can be measured with the fuel level sensor “Strela”?

You may use fuel level sensor “Strela” for diesel fuel, petroleum and oil measurement.

How to choose the right model of the fuel level sensor?

You should choose the model of fuel level sensor proceeding from the input type of terminal or other data processing unit.

The most widespread types of input:

1. Analogue input

2. Digital input (RS232 or RS485)

3. Frequency input.

If the terminal has both the analogue and digital input choose the digital one because digital input will give more precise data.

 What specifications of an analogue input influence measurement quality?

The analogue input range and number of digits of analog-to-digital converter influence measurement quality. For example, terminal AutoGRAPH-GSM has a 10-bit analogue input with a range of 0-10 V. It means that if we connect the sensor with an analogue output 0-10 V we receive 1024 gradation on sensor height. If the 10-bit input has a range of 0-30 V, it means that having connected the sensor with output signal 0-10 V we use only third of its enable, that is 1024/3=341 gradation. That is quite enough too.

Some terminals have 8-bit analog-to-digital converter with an analogue input; that is maximum 256 gradations even if the range of sensor output signal is equal to the analogue input range.

 What qualities should have a terminal for good fuel level sensing?

Except input range and number of digits of an analog-to-digital converter algorithm of data processing is important. It is strongly recommended to average analogue or frequency input data for the GSM-terminal (digital sensors has a function of data averaging and producing).

Wrong algorithm: once per 20 seconds value of fuel level is transferred to the server in a protocol packet, and the server averages it. In this case even if you send data to the server rather often (remember about traffic) still it will not be possible to have good results.

Right algorithm: the terminal interrogates a sensor, for example, every second, and once a minute sends a protocol packet to the server with the fuel level averaged for a minute. The further averaging and graduation is made by the server. In this case there is no need to send the data often and the result is much better.

What should I do if vehicle has more as one tank?

We can work with any tank number of any form and volume if you can connect several sensors to tour device and if your device or server/user software allow to process data from two or more sensors. If your GPS-device has only one input (analogue, frequency or RS 232) so you can use our summator-device, which can work with 1-4 Strela F sensors on input and give to output result from this sensors in form of voltage, frequency or RS232 signal. Calibrating tables are stored in this device and at output you receive the analogue, frequency or digital signal proportional to total fuel volume in tanks.

The customer wants to install the sensor only in a standard hole and does not want to drill a tank. How to make the standard level indicator work?

We offer signals interface unit (to work with many sensors) or signals interface unit Light (to connect only one sensor) for this case. Except for summing up the volumes on tanks there is an adjusted output on standard indicator and a rest lamp.

But we recommend to install sensors always in geometrical center of tank, the standard hole installation is just exeption from rules.

The sensors works badly, schedules are awful – where is the problem?

The sensor task is not to create good schedules. The sensor produces a signal - in the form of voltage, frequency or messages. Analogue signal can undergo hindrances; the system can be affected by badly connected ground. Frequency and digital sensors are better protected against external hindrances.

The sensor is in working order when it forms correctly an input signal at lifting and lowering it in capacity with fuel. If it works well in your hands but badly in the car - the sensor is in working order.

Always check whether the internal tube doesn’t dangle and whether there is no dirt between tubes.