Engineers developing remote monitoring systems for off-grid assets face significant power consumption constraints. This story details a solution for a company needing to measure fuel levels in stationary tanks using a battery-powered system. The application required a sensor that could not only run on a low voltage supply but also withstand being powered on and off frequently to conserve energy. The solution was a submersible hydrostatic level transmitter which directly addressed these challenges with its specialised low-power output and robust design.
- Customer Application: Remote, intermittent monitoring of fuel level in stationary tanks.
- Critical Constraint: Must operate on a low-power, 5Vdc battery/solar system.
- Unique Challenge: Sensor must tolerate frequent power cycling to conserve energy without affecting performance or lifespan.
- Product Solution: A submersible hydrostatic level sensor featuring a 5Vdc ratiometric output and fuel-compatible materials.
A product manager specialising in advanced solutions for fleet management and remote asset tracking was tasked with developing a system to monitor the fuel levels in stationary tanks. A primary challenge for this application was that the tanks were often situated in remote, off-grid locations with no access to mains electricity. The monitoring system would therefore rely on a battery, likely supplemented by a solar panel. This operational constraint dictated a critical need for a level sensor with very low power consumption. Furthermore, to maximise battery life, the system’s telemetry unit would power the sensor on only for brief, intermittent periods to take a reading before powering it off again. The sensor had to be robust enough to handle this frequent power cycling while providing a stable and reliable output.
The ideal sensor needed to operate directly from a 5Vdc power input and provide a corresponding voltage output, which the company’s data logging equipment was designed to accept. The initial search identified some potential ceramic level transmitters, but a more specialised solution was required to meet the specific 5Vdc power supply and low-power intermittent operation requirements. The application also demanded a simple installation method suitable for retrofitting onto a wide variety of existing tanks without requiring significant and costly mechanical work, such as drilling or welding new process connections.
The proposed solution was the IMTG series submersible tank gauging level transmitter. This device is specifically designed for measuring liquid levels in small tanks and containers where continuous submersion is necessary, making it ideal for monitoring fuels like diesel. The key to its suitability for this low-power application was the availability of a ratiometric voltage output. Unlike a standard 4-20mA loop transmitter which requires a higher supply voltage of 9-32Vdc, the ratiometric 0.5 to 4.5Vdc output option is designed to run from a 5Vdc supply. This feature is particularly advantageous in battery-powered systems. A ratiometric output’s signal is proportional to the supply voltage, meaning that minor fluctuations or drops in the battery’s voltage do not compromise the measurement’s accuracy, eliminating the need for a separate, power-consuming voltage regulator circuit for the sensor.
The sensor’s design is inherently robust, built around a stable piezo-resistive silicon pressure sensor with an operational life of over 100 million cycles, ensuring it can withstand the frequent on/off power cycling required for energy conservation. Installation is straightforward; the sensor is simply lowered to the bottom of the tank from an access point at the top. This method is perfect for sealed or underground tanks where external access to the bottom is not feasible. Material compatibility with the fuel was also crucial. The selected configuration, featuring a stainless steel housing, a 303 stainless steel diaphragm, Viton seals, and a fuel-resistant FEP cable sheath, ensures long-term reliability and accurate performance when continuously immersed in diesel fuel.
IMTG Low Powered Fuel Tank Level Sensor
- Part No: IMTG-G0100-AA4-CAV-002-000
- Pressure Range: 0 to 1 mWG
- Reference Type: Gauge / Vented (atm to +P)
- Output Signal: 0.5 to 4.5Vdc, ratiometric
- Non-Linearity and Hysteresis: 0.5% FS
- Thermal Zero Shift: 0.04% FS per =C2=B0C
- Temperature Sensor: None
- Housing Material: Stainless Steel 303
- Diaphragm Material: Stainless Steel 316L
- Media Exposed Seals: Viton
- Cable Type: FEP
- Cable Length: 2
- Cable Length Units: Metres (m)
- Process Connection: Nose cone with self draining M7x1 test port