An automation company required a dependable method for monitoring water levels in tanks situated in the remote Caribbean, where water is a scarce resource. The primary challenge was to transmit real-time level data and alarms over the internet from locations with limited infrastructure. The chosen solution pairs a robust submersible hydrostatic level sensor with a cellular IoT gateway, creating a complete remote monitoring package that ensures data accuracy and reliable communication.
- Application: Monitoring critical water levels in residential water tanks in a remote island location.
- Challenge: Achieving reliable, real-time data transmission and alarm functionality from assets in areas with limited local internet access.
- Solution: An SLS-A series submersible level sensor connected to an IoT-Gateway Lite for cellular data transmission.
- Connectivity: The system utilizes the lightweight MQTT protocol to efficiently send sensor data over a 2G/4G cellular network to a cloud monitoring platform.
An automation solutions provider based in the Caribbean was tasked with developing a system for remotely monitoring water levels in tanks on an island. Due to the limited availability of fresh water in the region, maintaining a consistent and reliable supply for residential properties is a critical concern. The client required a solution that could provide continuous, real-time level data and transmit alarms to a central monitoring station via the internet when levels fell below a predefined threshold. A key challenge was the remote location of the tanks, which necessitated a robust and self-contained monitoring system capable of reliable data transmission from areas with potentially limited infrastructure outside of cellular networks. The system also needed to be versatile, with one option for a standalone monitoring package and a second option that could integrate with existing third-party home automation controllers.
The proposed solution comprised two core components: a submersible level sensor for direct measurement in the water tanks and a dedicated IoT gateway for data processing and transmission. For the sensing element, the SLS-A series submersible level transmitter was selected. This sensor is specifically designed for continuous immersion and uses a piezoresistive silicon sensing element protected by an isolated stainless steel diaphragm and housed in 316 stainless steel. For this application, a measurement range of 0 to 5 metres water gauge (mWG) was chosen to match the depth of the tanks. The sensor was configured with a raw millivolt-per-volt (mV/V) output signal, a low-power option ideal for pairing with battery or DC-powered field instrumentation.
To meet the critical remote monitoring requirement, the sensor was paired with the IoT-Gateway Lite. This compact cellular gateway is engineered to serve as a bridge between field sensors and a remote cloud server. It is specifically equipped with a mV/V input to directly interface with the SLS-A sensor, simplifying the system architecture. The gateway uses a built-in 2G/4G cellular modem to transmit the collected level data using the Message Queuing Telemetry Transport (MQTT) protocol, a lightweight and efficient standard for IoT communications that is ideal for sending data over cellular networks. This data is sent to a secure, firewall-protected cloud platform, allowing the end-user to monitor tank levels in real-time, view historical data trends, and receive automatically generated SMS or email alarm notifications from any internet-connected device, such as a smartphone or PC. This combination of a durable, vented submersible sensor and a dedicated cellular IoT gateway provides a complete, standalone solution for critical water resource management in a challenging remote environment.
SLS-A Submersible Hydrostatic Level Sensor
- Part No: SLS-A-AA-A005-BV-0500G-00
- Level Range: 0 to 5 mWG
- Range Type: Gauge, Vented Reference
- Output Signal: mV/V
- Accuracy Class: 0.25%
- Cable Type: PUR
- Cable Length: 5
- Cable Length Units: Metres (m)
- Housing Material: 316 Stainless Steel
- Seal Material: Viton
- Diaphragm Material: 316 Stainless Steel
IoT-Gateway Lite Version Cellular Transmitter
- Part No: IoT-Gateway-Lite-00
- Analogue Inputs: 1 x mV/V 4-wire & 1 Analogue
- Digital Inputs: 8 x Volt-free Digital Inputs
- Outputs: None
- Display: None
- Options: None
- Cellular Connection: 2G/3G/4G Transmit Bands MQTT Protocol
- Power Supply: 12-36Vdc