The ER-BLE sensor is designed to measure the level of fuel in tanks and fuel tanks of vehicles, as well as in stationary fuel storage facilities, when wiring is not possible or too time-consuming.
The ER-BLE sensor can also be used to measure the level of other non-conductive liquids.
The measuring head of the sensor performs a linear conversion of the capacitance of the measuring probe into a digital fuel level code, processing of the received digital data with averaging of measurement results, measuring the temperature of the head and data output via the wireless BLE interface.
Main advantages:
- High-resolution of the sensor, linearity, temperature stability;
- Calibration table inside the sensor head. Allows transferring data directly in liters;
- Up to 5 years of battery life;
- Monolith construction;
- Wide range of possible probe length from 15 to 300 cm;
- Ease of installation. Any hack saw can be used to cut the probe.
Sensor description
The Epsilon-ER-BLE - wireless fuel level sensor is designed to measure the level in tanks and fuel tanks of vehicles and stationary fuel storage facilities. The sensor can be used to measure the level of other non-conductive liquids. The sensor can be used together with an external data acquisition unit (GPS monitoring equipment) that supports BLE technology (“Bluetooth Low Energy” - Bluetooth specification with ultra-low power consumption).
Additional features
The BLE Sensor Reader(s) is designed for wireless acquisition of sensor data and transmission of the read data to an external data acquisition unit (GPS monitoring equipment) via the RS-485 (BTR4/BR4x models) or RS-232 (BTR2/BR2x models) interface. The Reader uses the LLS binary protocol to transmit the read data. The Readers are also used to introduce changes to Sensor settings during installation or operation. For this purpose, in addition to the above-mentioned models, it is possible to use a BRU2 Reader with an USB interface.
The Sensor and Reader can be used on motor vehicles, agricultural machinery, stationary tanks and other facilities.
Data transmission by the Sensor (between the Sensor and the Reader) is carried out via a radio channel at a frequency of 2.4 GHz. The Sensor periodically transmits pre-programmed system-specific identifiers, as well as measured temperature and fuel levels. The Reader selects Sensors with the identifiers of this system and transmits the received data to an external data acquisition unit. One Reader can simultaneously receive information from 50 Sensors.
If an external data acquisition unit (GPS monitoring equipment) has a built-in support for BLE technology, then you are required to use the Reader only if you make changes to the Sensor settings.
Operation principle
The fuel level is measured by a sensing head integrated into a single unit with a measuring probe immersed in the fuel. The Sensor is attached to the tank using self-drilling screws. The tightness between the tank and the flange is ensured by a gasket.
The measuring probe is a coaxial capacitor that is formed by an aluminum alloy tube (external electrode) and an insulated aluminum rod (internal electrode). The necessary alignment of the rod is provided by a plug located at the end of the measuring element and internal spacers-insulators. The capacity of the Sensor's measuring probe depends linearly on the fuel level.
The sensing head of the Sensor contains:
- a capacity meter;
- a digital data processing scheme;
- a wireless data exchange device;
- a lithium battery and power stabilizer.
The capacity meter converts the current probe capacity to a digital code. The digital data processing circuit controls the meter, provides the required measurement range, performs linear conversion of the capacity code to a digital fuel level code, processes the received digital data, performs thermal compensation, filtration (averaging) and scaling of data, and measures the temperature of the head.
The wireless data exchange device provides the ability to exchange data with the monitoring device, save/load Sensor calibration and configuration data, and remotely update the firmware using BLE technology. The Sensor periodically emits signals (beacon mode) with its ID and data such as owner ID, Sensor Group ID, battery voltage, signal strength for measuring the distance to the Reader, temperature and fuel level code. An identifier (Sensor number in the group), owner ID, Sensor Group ID, password for receiving Sensors, radio channel number, password for connecting to the Sensor and changing its settings are configured for each Sensor.
Fuel level data are displayed as a 16-Bit value, and temperature data are displayed as an 8-Bit value. To determine the volume of controlled fuel, it is required to perform the fuel tank calibration procedure, which establishes the relationship between the fuel volume and the level code.
Installation of the sensor
Evaluation of fuel probe length when ordering
To evaluate the proper fuel probe length it is necessary to measure fuel tank depth in place of intended sensor installation and to calculate length of fuel probe according to the formula:
Lm = L- Δ,
where Lm – approximate length of fuel probe as per order;
L– tank depth in place of intended sensor installation;
Δ - distance between measuring part and tank bottom.
Recommended values for distance Δ:
- Δ = 15…20 mm – for rigid metal tanks (the deeper the tank the bigger the distance);
- Δ = 30 mm – for tanks without enough rigidity (such as plastic tanks of considerable height).
During installation process, the necessity of reducing fuel probe length may arise (on-site).
You can find the procedure of reducing fuel probe length in “EH.000-EN IM_ Installation Manual”.
Technical characteristics
| Parameter or characteristic name | Unit | Value | Notes |
|---|---|---|---|
| Operational temperature range | °C | – 40 … + 75 | |
| Mode of operation | Continuous | ||
| Reduced level measuring error | % | ± 1,0 | |
| Resolution | mm | 0.1 | |
| Data sending period | sec | 1.2 | |
| Response time to level changes | sec | 35 | |
| Supply voltage (lithium battery) | V | 3.6 | |
| Continuous battery life | years | 5 | |
| Operating frequency range | GHz | 2.400 ... 2.485 | |
| Radiation power | dBm | 0 | 1 mW |
| Bit size of the code for presenting measurement results, bit | bit | 16 | level |
| 8 | temperature | ||
| Data reading maximum range | m | 20 | |
|
Value range of the relative dielectric constant of operating fluid (ε) |
1.5 … 5.0 | ||
| Degree of protection of the sensing head against dust and moisture penetration | IP67 |
