Remote monitoring has a power problem. Solar panels shrink, battery packs need to last seasons rather than weeks, and every microamp matters. Yet the pressure data those sites produce, groundwater levels, mains pressure, irrigation flows, pipeline integrity, has never been more critical to the organisations relying on it.
The Titan TPT-SDI Digital Pressure Transmitter from Stork Solutions is engineered specifically for this reality: precise pressure measurement, digital output, and a power budget low enough to live on a small battery or modest solar panel for years at a time.
Why SDI-12 changes the economics of remote monitoring
Most legacy pressure transmitters use 4–20 mA analogue output. It’s well-understood and widely supported, but it carries some real cost on a remote site:
- One transmitter typically requires its own pair of wires back to the logger.
- Long cable runs with high installation costs can become expensive.
- Each transmitter draws current continuously, a problem when your power source is a 12 V battery and a solar panel the size of a paperback book.
SDI-12 was designed to solve exactly these problems for environmental and hydrological networks. It’s a low-power, addressable, digital serial protocol that lets you daisy-chain multiple sensors on a single three-wire cable, with the data logger polling each one in turn by address.
The TPT-SDI implements native SDI-12 v1.4, not bolted on via a converter, but built into the sensor’s onboard 16-bit microprocessor. That means linearisation, temperature compensation and calibration are all handled inside the sensor, and what comes out is a clean digital reading that doesn’t degrade over cable length.
Built for battery and solar
The numbers tell the story:
- <250 µA idle current
- <4 mA active current for short measurement times
- 6–36 V dc supply range
That power profile is purpose-built for solar telemetry stations, battery-powered loggers, and remote terminal units (RTUs), installations where conventional transmitters would flatten the power budget on their own. Combined with integrated lightning protection (gas discharge tube) and an IP67-capable enclosure, the TPT-SDI is designed to sit unattended in a roadside kiosk, riverbank enclosure or borehole headworks for years at a stretch.
Ceramic precision in a stainless body
At the heart of the TPT-SDI sits a 96% Aluminium Oxide (Al₂O₃) ceramic piezo-resistive sensing element inside a 303/316 stainless steel body. Ceramic offers outstanding corrosion resistance, which matters in groundwater, borehole, fire hydrant and wastewater applications where media can be anything but friendly, and where stainless-only diaphragms can struggle over time.
With the onboard processor handling the maths, the sensor delivers:
- ≤±0.25% FS standard accuracy, with ≤±0.10% FS as an option (BFSL).
- Pressure ranges from 0.5 bar up to 600 bar (gauge, sealed gauge, absolute).
- Calibrated temperature output alongside pressure — useful for both diagnostics and process correction.
- Long-term stability of ≤±0.10% FS, supporting multi-year deployment cycles.
Mechanical and electrical options
The TPT-SDI is supplied with options that match real-world installation needs:
- Electrical connections: M12 x 1 4-pin, integrated cable outlet (IP65 / IP67), or Mini DIN 43650.
- Process connections: G¼” DIN 3852, ¼” NPT, or Series 21 quick release.
- Configurable part numbering — making it straightforward to specify exactly the variant you need.
For benchtop configuration, calibration checks and lab work, the sensor pairs with the optional USB-SDI12-PRO interface adaptor and configuration software, letting you poll and log readings directly from any PC.
Where the TPT-SDI shines
- Hydrology and environmental monitoring — surface water level, groundwater and borehole monitoring, integrated with the SDI-12 data loggers already standard in the water industry.
- Water network monitoring — mains pressure, leak detection, fire hydrant flow validation, distribution pressure profiling.
- Irrigation and pipeline telemetry — multi-sensor SDI-12 daisy-chains reducing cable, labour and ongoing maintenance.
- OEM smart infrastructure — embedded into portable test kits, monitoring products, and smart asset devices.
- Research and academia — paired with the USB-SDI12-PRO adaptor as a stable, digitally calibrated pressure reference for teaching and instrument development.
- Geotechnical and agricultural monitoring — long-duration unattended studies where data integrity and minimal power consumption decide whether the project succeeds.
Complementary products from the Stork range
The TPT-SDI is often deployed as part of a wider sensor network. Several products from the Stork digital pressure sensors range and the temperature transmitters range work naturally alongside it:
- SLS-D Digital Submersible Level Transmitter – SDI-12 — a perfect partner on SDI-12 networks for combined level and pressure monitoring, sharing the same bus and power architecture.
- STT-28 SDI-12 Submersible Temperature Transmitter — adds calibrated water or media temperature on the same SDI-12 bus, ideal for hydrological and environmental sites that need both pressure and temperature.
- SSTT Subsea Temperature Transmitter — for deeper, higher-integrity subsea installations where the TPT-SDI may sit alongside temperature instrumentation in a wider deployment.
- Titan TPTd Digital Pressure Transmitter — for sites that need a higher-bandwidth digital interface than SDI-12 (e.g. Modbus or IO-Link environments), often used in industrial process installations.
- DCT 531 / DCT 561 Industrial Pressure Transmitters with RS485 Modbus RTU — useful where part of a network is industrial Modbus and part is field SDI-12; the two protocols frequently co-exist in mixed water utility installations.
For typical environmental and water-industry deployments, pairing the TPT-SDI + SLS-SD/SLS-CD + STT-28 on the same SDI-12 bus gives you pressure, level and temperature from a single low-power network, polled by a single logger.
The takeaway
The TPT-SDI is what you specify when you need lab-grade pressure accuracy at the end of a long cable run, on a small battery, for years. Native SDI-12, ceramic sensing, ultra-low current draw and rugged stainless construction make it a natural fit for the water industry, environmental agencies, irrigation networks, and OEMs building the next generation of low-power smart instruments.
For the full datasheet and configuration options, visit the TPT-SDI Pressure Transmitter with SDI-12 product page or explore the wider digital pressure sensors range.
