Safiery STLS01 submersible water tank level sensor IP68Submersible pressure sender for drinking-water tanks, 0–5V

Overview

STLS01 is Safiery's submersible tank sender: a fully sealed pressure transducer that is lowered into a drinking-water tank on its integrated cable, so no fitting is needed at the bottom of the tank. A piezo-resistive ceramic cell in a 304 stainless steel housing, rated food grade and IP68, turns the water depth into a 0–5V signal from a 12V DC supply, with accuracy within ±1% of full scale and a response time of 10ms or less. Its voltage output connects to a Victron GX Tank 140 or a Simarine ST107.

• Pressure senders with 0–5V output and 12V DC supply
• External bottom-fitting and submersible IP68 versions
• Wema-style stainless float senders on SAE 5-hole flange
• Voltage senders connect to a Victron GX Tank 140
• Simarine ST107: 4 resistive and 3 voltage inputs
• 2-year warranty on pressure sensors and Simarine products

Sender types

The pressure senders measure the weight of the liquid column with a piezo-resistive ceramic cell behind a stainless steel diaphragm and turn it into a 0–5V signal from a 12V DC supply. STLPO01 and the compact STLPO02 screw into a fitting at the bottom of the tank from outside; the STLPS01 submersible sender hangs inside the tank on its sealed cable and is rated IP68 for drinking water.

Wema-style senders work mechanically: a float carrying magnets slides along a stainless steel tube and closes reed switches inside it, giving a resistance that falls from 240Ω to 33Ω in steps of 21mm. The float is the only moving part, the senders suit fuel, oil and water, and they bolt onto the standard SAE 5-hole pattern in 200, 400 or 450mm lengths.

Connecting to Victron and Simarine

Voltage-output senders connect to a Victron GX Tank 140, which reads up to four 0–10V sensors; lower and upper limits are set on the GX for a 0–5V signal, together with fluid type, tank shape and an averaging time of 1–60 seconds. Channels 3 and 4 supply 24V to the sensor, channels 1 and 2 pass on an external supply. Safiery wires its resistive Wema senders directly to a Cerbo GX or a Simarine monitor.

On Simarine systems the ST107 module adds four resistance inputs for 0–65kΩ senders or NTC temperature probes and three voltage inputs for voltage senders or voltage-only batteries. It links to a PICO display over SiCOM, where each sender is calibrated, and offers a programmable 1A alarm contact.

Installation notes

External pressure senders need a threaded G1/4in port at the bottom of the tank, while the submersible type is lowered into the tank on its cable. Safiery recommends shielded sensor cable with the shield bonded to bare metal of the vehicle or boat. Every sender has to be calibrated on the display it reports to. The ST107 belongs in a clean, dry place; SiCOM runs of 5m or more need 2×2×0.25mm² twisted pair.

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