Key Features Of The SLS-SD SDI-12 Submersible Level Sensor
SDI-12 Version 1.4 Interface
A digital output that connects directly to SDI-12 data loggers and telemetry units.Level And Temperature As Standard
Both measurements are returned by the same sensor over the same cable.Accuracy To ±0.06% FS
Three accuracy classes of ≤ ±0.15%, ≤ ±0.10% and ≤ ±0.06% FS with 16-bit compensation.Built-In Density Correction
The integrated temperature sensor allows correction for changes in liquid density.Ultra-Low Power
Less than 250 µA idle and under 4 mA active from a 6 to 36 VDC supply.Up To Nine Sensors On One Bus
Addressable sensors share a single cable run to the logger.
Applications For SDI-12 Level Sensors
The SLS-SD is built for unattended level monitoring on SDI-12 logging networks:
- Rivers, reservoirs and boreholes – continuous water level monitoring in open water and groundwater.
- V-notch weir flow measurement – accurate head measurement for open-channel flow.
- Environmental monitoring – long-term level records for hydrology studies.
- Flood defense monitoring – early warning and research on rising water levels.
- Telemetry and data logging – direct digital connection to SDI-12 loggers and RTUs.
- Academic research – field and laboratory studies.
Why Choose An SDI-12 Level Sensor?
SDI-12 is a digital communications standard created for environmental monitoring. The data logger wakes each sensor, requests a measurement and receives calibrated values over a single data line. Between readings the sensor sleeps, so average power use is very low, which matters at remote sites running on batteries or solar panels.
Because each sensor has its own address, up to nine SLS-SD sensors can share one cable back to the logger. Readings arrive as engineering values, so there is no analog scaling to set up, and the supporting SDI-12 software can be used to calibrate the sensor, apply density correction, log data and diagnose communications.
Power And Communications
- Interface – SDI-12 version 1.4
- Measurements – level and temperature
- Supply voltage – 6 to 36 VDC
- Current consumption – under 250 µA idle, under 4 mA active
- Sensors per bus – up to 9
Level Ranges
Ranges are specified in meters of water gauge (mWG).
| Range (mWG) | Approx. Depth (ft of water) |
|---|---|
| 0.5 | 1.6 |
| 1 | 3.3 |
| 2.5 | 8.2 |
| 3.5 | 11.5 |
| 5 | 16.4 |
| 10 | 32.8 |
| 20 | 65.6 |
| 30 | 98.4 |
| 50 | 164 |
| 100 | 328 |
SLS-SD Submersible Level Sensor Technical Specifications
| Specification | Detail |
|---|---|
| Product Type | Submersible hydrostatic level sensor, SDI-12 digital output |
| Sensor Technology | Silicon piezo-resistive, isolated diaphragm |
| Digital Interface | SDI-12 version 1.4, up to 9 sensors per bus |
| Measurements | Level and temperature |
| Level Ranges | 0.5, 1, 2.5, 3.5, 5, 10, 20, 30, 50, 100 mWG |
| Pressure Reference | Gauge (standard), sealed gauge, absolute |
| Accuracy | ≤ ±0.15%, ≤ ±0.10% or ≤ ±0.06% FS (range dependent) |
| Safe Overpressure | 1.5 x rated range |
| Burst Pressure | 3 x rated range |
| Long Term Stability | ≤ ±0.10% FS |
| Supply Voltage | 6 to 36 VDC |
| Current Consumption | < 250 µA idle, < 4 mA active |
| Signal Processing | 16-bit microprocessor with density correction |
| Thermal Effects | ±0.01% FS/°C |
| Housing And Sensor Material | 316 stainless steel |
| Seals | FKM, EPDM or NBR |
| Compensated Temperature | 0 to +40 °C |
| Media Temperature | -10 to +60 °C, non-freezing |
| Cable | PUR submersible cable with internal vent tube, terminated in tails |
| Cable Connection | G1/4 DIN 3852 male thread when nose cone is unscrewed |
| Ingress Protection | IP68, fully submersible to 100 m |
| Surge Protection | Internal protection; external protection devices recommended |
| Weight | Sensor < 300 g; cable 48 g per meter |
| Conformity | CE |
| Accessories | USB communications interface, vented junction box, cable hanger |
SLS-SD SDI-12 Level Sensor FAQs
What does the SLS-SD measure?
The SLS-SD reports both liquid level and temperature as standard over its SDI-12 interface.
How many SLS-SD sensors can share one logger port?
Up to nine sensors, each with its own address, can be connected to a single SDI-12 bus.
How much power does it use?
Less than 250 µA when idle and less than 4 mA when measuring, from a 6 to 36 VDC supply, which suits battery and solar-powered sites.
What is density correction?
Liquid density changes with temperature, which slightly alters the pressure at a given depth. The SLS-SD uses its built-in temperature sensor to correct for this and improve level accuracy.