SIGMA ULS non-invasive ultrasonic level sensor. Can be used to measure level of liquids in reservoirs, including LPG in the vehicles tanks. Sensor is fastened to the bottom of the tank and do not have direct contact with the liquid. The device allows us to measure level of water, LPG (propane-butane) and other fluids. Sensor is compatible with various control units, data concentrators and GPS tracking equipment.
Key features:
- Low cost;
- Non-invasive;
- Easy installation;
- Measuring error 2%.
Sensor description
Ultrasonic level sensor “SIGMA” allows with high accuracy to determine LPG consumption from one refueling to another and plan a visit to the gas station.
The sensor uses ultrasonic measuring principle. Ultrasonic wave goes from the bottom of the tank to the top, reflects and goes back to the bottom.
Operation principle
Sensor consists of two parts - measuring part and transducer with indicator (hereinafter - Transducer).
| a | b | ||
| Typical LPG fuel containers layout and recommended position for sensor measuring part installation in passenger cars (a - toroidal container, b - cylindrical container) | |||
Transducer calculates fuel level by processing data from the measuring part and outputs result to the indicator. Calibration procedure is performed to indicate fuel volume instead of fuel level. After the calibration, fuel level (in centimeters) is recalculated into volume (liters). Measuring results are demonstrated on the indicator; they can be also transferred to the GPS tracking device for further processing.
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Converter calculates fuel level according to the measuring device data and shows readings on the indicator display in liters. Indicator displays the remaining amount of fuel in its basic operation mode. Typical placement of converter with the indicator (it can also be mounted on a horizontal surface using the mounting bracket from the delivery pack) |
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To determine the filled-in fuel during refueling: you should press Button 1 (lower one) before refueling, then you should press Button 2 (upper one) to set up the reference level of fuel. |
There are 3 modifications of SIGMA ULS sensors, which have different data interface for setting:
SIGMA ULS - no data transfer interface (setting by battons);
SIGMA ULS2 - RS-232 interface for setting;
SIGMA ULS4 - RS-485 interface for setting.
To protect the sensor from mechanical influences and unauthorized access to the sensor and its mounting system, a ULM.4000 protection device can be used (optionally) on horizontally located fuel gas ballons up to 450 mm in diameter mounted outside the vehicle.
Sensor installation does not interfere with the tank structure or influence autogas equipment operation.
Sensor can be used with equipment that supports unified communication protocol Epsilon Data Exchange.
Installation of the sensor
The best places for measuring part installation are cavities and hollow spaces in the vehicle trunk bottom. Distance between the bottom, trunk walls and measuring part must be no less than 5 mm (see picture). To achieve this, rubber spacers may be used. Spacers must be positioned in a way that container remains in horizontal position.
Another solution for installation can be cutting Ø 40 – 50 mm hole in the trunk bottom, where the measuring part can be placed. Hole can be hermetically sealed afterwards with a slab of rubber sheet or with matching blanking plug (user-supplied).
Measuring part working surface should be parallel to fuel surface, in other words – horizontally.
Potential installation place of measuring part on a toroidal container
Considering information above, chose two, three potential installation places of measuring part, clean them from dirt and rust, degrease and mark them.
Tank calibration
Calibration could be done in 2 ways:
- using digital indicator
- using installation software
Each of this ways could be performed as in automatic so manual mode.
For more detailed information please read installation manual in the download section.
Technical characteristics
| Description | Unit | Value | Notes |
|---|---|---|---|
| General | |||
| Type of measured fuel |
|
LPG | |
| Allowed tilt angle of vehicle when measuring level, max | degrees | 12 | |
| Container wall thickness | mm | 1,5…4,0 | |
| Operational temperature range | oС | – 40 … + 70 | |
| Measuring part ingress protection rating | IP67 | ||
| Transducer ingress protection rating | IP50 | ||
| Mode of operation | Continuous | ||
| Measurments | |||
| Indicator resolution capability | liters | 1* |
|
| Measurement range | mm | 20…600** | |
| Averaging period | sec. | 30 |
|
| Code length of presentation of measurement results | bit | 10/12/16 | Level |
| 8 | Temperature | ||
| Exchange rate through the serial port | bps | 2400, 4800, 9600, 19200, 38400, 57600, 115200 | Programmed, default setting - 19200 |
| Power Supply | |||
| Power supply voltage, operational range | V | +9 …+36 | Nominal value |
| Current consumption, max | mA | 70 | |
| Interface | |||
| Digital | RS-485 | ULS4 model | |
| RS-232 | ULS2 model | ||
| Dimensions | |||
| - transducer, max | mm | 62х38х16 | |
| - measuring part, max | mm | ∅26х11 | |
Notes to table:
* - Indicator readings are considered adequate in 30 seconds after the filling-in if the vehicle stays in horizontal position.
** - When level of fuel in tank is lower than the minimal measuring range of sensor, readings can be incorrect. It is recommended to fill in before fuel reaches lower measuring range of sensor.
