Magnetostrictive Level Transmitter — Magnetic Float & Interface, SGM / SE-LX Series, OEM China
SEGMENsensor magnetostrictive level transmitters deliver continuous, absolute liquid-level measurement using a magnetic float riding on a magnetostrictive waveguide probe. Series SGM-LS10, SGM-LC10, SGM-LK10 and flameproof SE-LX10 / SE-LX20 / SE-LX30, 25–8000 mm, with oil-water interface on SE-LX20 / SE-LX30. 4-20mA, 0-10V and RS485 Modbus + HART (parameters settable with a HART handheld communicator). IP67/IP68. OEM from Shenzhen since 2019, OEM volume supply.
A SEGMENsensor magnetostrictive level transmitter measures liquid level continuously by timing a torsional pulse along a waveguide probe to the magnet inside a float. It reports the float's absolute position without density compensation. Six part numbers cover 25–8000 mm, including flameproof SE-LX models that read oil–water interface with a second float.
SGM-LS10 covers 25–8000 mm, SGM-LK10 25–4000 mm and the PP/PFA SGM-LC10 25–1000 mm, all IP68.
The flameproof SE-LX10, SE-LX20 and SE-LX30 cover 200–8000 mm and are rated IP67.
Outputs are 4-20 mA, 0-10 V and RS485 Modbus, with 2-wire 4–20 mA + HART (parameters settable with a HART handheld communicator).
SE-LX probes run from -40 to +85 °C, or to +250 °C in the high-temperature version.
Qualification samples are 1–5 pcs for every part number; quotes are FOB China.
Last updated · SEGMENsensor Engineering Team
Watch: magnetostrictive level transmitter installation and wiring
Magnetostrictive Level Transmitter: How It Works, Installation and WiringHow a float and waveguide measure absolute level, which model fits your tank, installation, 2-wire 4–20 mA or RS485 wiring, and scaling the signal.
Magnetostrictive level transmitters: how they work, which one to choose, and how to install and wire one. A float with a built-in magnet rides on a stainless steel rod. Inside the rod runs a thin waveguide wire. The electronics send a current pulse along the wire. Where it meets the field of the float magnet, the wire twists, and a torsional wave travels back to the head. Its travel time gives the float position: an absolute level reading, with no recalibration after a power loss. A second float can measure the interface between two liquids. Pick the model for the tank. The SGM-LS10 stainless rod covers 25–8000 mm. The SGM-LC10, with a PP head and PFA float, is for corrosive liquids. The SE-LX20 has a flameproof housing and a rigid rod, with level and interface floats. The SE-LX30 uses a flexible cable for tall tanks. Mount the transmitter vertically on the tank top, by thread or flange. The float must pass through the nozzle, or be fitted from inside the tank. Keep the rod away from the inlet stream and the agitator, and use a stilling well in turbulent tanks. Check the inactive zones at the top and bottom of the rod before you set the range. Wiring: on 2-wire models, one cable pair carries the 24 V supply and the 4–20 mA signal to the PLC analog input. RS485 models report the level over Modbus RTU. Scale it like any 4–20 mA signal: subtract 4 mA, divide by 16, and multiply by the range. On the production line, rods and flanges are laser-welded, and the return signal of each sensor is checked on an oscilloscope. The reading is then checked on a test bench, and the nameplate is laser-marked. Before you order, specify the range, output, process connection, float material and temperature. Repeatability is ±0.005 mm on the SGM-LS10. SEGMENsensor magnetostrictive level transmitters. OEM volume supply. Datasheets and quotes at segmensensor.com.
Magnetostrictive Position Sensors: Production and TestingReal production footage of SEGMENsensor magnetostrictive position sensors: electronics assembly, laser welding of rods and flanges, burn-in, signal test on an oscilloscope, calibration on a linear test bench and laser-marked nameplates.
Magnetostrictive position sensors: how SEGMENsensor builds and tests them. It starts with the electronics. Each sensor board is soldered by hand and fitted into the sensor head. The head, cable and connector are assembled on the housing, and heat-shrink sleeves seal the wiring. Rods and flanges are joined by laser welding on a rotary fixture, with a camera to align each seam. The electronics then run on a burn-in rack. Every sensor is tested. The oscilloscope checks the return signal, and a meter checks the output. Each sensor is then calibrated on a linear test bench, where software checks its reading along the stroke. Finally, the nameplate is laser-marked with the model and the company name. Strokes 25–8000 mm · OEM volume supply · Request a quote at segmensensor.com
Stainless Steel Sensor Housings: Sealed and Leak-TestedProduction footage of stainless steel housings and rods for level and position sensors: machined housings, threaded process connections, pneumatic pressing and an air-pressure leak test under water for every sealed assembly.
Stainless steel housings and rods for level and position sensors. On the production line, machined stainless steel housings are sorted and checked before assembly. Sensor rods are fitted with threaded process connections. Parts are joined on a pneumatic press. Every sealed assembly is then leak-tested: it is pressurised with air and held under water, where any leak would show as bubbles. Request a quote at segmensensor.com.
Made and tested in our factory
Laser welding of magnetostrictive sensor rods and flangesMagnetostrictive sensor signal test stationLinear test bench for calibration over the full stroke
Every unit is tested before shipment. Photos from our own production and test lines.
What is a Magnetostrictive Level Transmitter?
A magnetostrictive level transmitter (also called a magnetic float level transmitter or magnetostrictive liquid level gauge) is a continuous level sensor built around a magnetostrictive waveguide probe and a buoyant magnetic float. As the float rides the liquid surface, the transmitter measures the float's absolute position by time-of-flight and outputs a 4-20mA, 0-10V or RS485/Modbus signal proportional to level. Unlike a hydrostatic probe, its reading does not depend on liquid density, and unlike a float switch it measures the full range continuously — with optional oil-water interface (two floats on SE-LX20 / SE-LX30) in the same instrument.
Magnetostrictive Level Sensor Series — Choose by Part Number
Six SGM / SE level series, each with its own page, specifications, ordering code and two-page datasheet. SE-LX models are flameproof with a local display. OEM volume supply.
±0.005 mm (SGM-LS10, SGM-LK10); <±0.001% FS, min ±10 µm (SGM-LC10); ±1 mm / ±0.1 mm (SE-LX)
Non-Linearity
<±0.05% (SGM-LC10); ±1 mm (SE-LX)
Interface Measurement
Two floats for level + interface on SE-LX20 / SE-LX30
IP Rating
IP68 (SGM-LS10, LC10, LK10); IP67 (SE-LX)
Materials
Stainless rod (SGM-LS10, SGM-LK10); PP head with PFA float (SGM-LC10); flameproof housing (SE-LX)
Supply Voltage
24V DC (standard; 12 V and 5 V ranges depending on output and model)
Operating Temperature
-40°C to +85°C; SE-LX rod -40~+85℃, -40~+250℃ (high-temperature version)
Hazardous Area
SE-LX10 / LX20 / LX30 flameproof
Samples
Samples 1–5 pcs for qualification; volume per project
Lead Time
Confirmed with the quotation
Certifications
CE, RoHS
Download the magnetostrictive level sensor datasheets (PDF)
One two-page datasheet per series: specifications, wiring, dimension drawings and ordering code for SGM-LS10, SGM-LC10, SGM-LK10, SE-LX10, SE-LX20 and SE-LX30. No registration required.
Explosion-protection markings: Ex db IIC T6 Gb, Ex ia IIC T6 Ga, Ex tb IIIC T80°C Db (hazardous-area model confirmed at order).
2-wire 4–20 mA + HART; parameters can be set directly with a HART handheld communicator.
Position sensors: resolution down to 0.1 µm; non-linearity ±0.01% FS; 10-point bench calibration.
Interfaces: analog 4–20 mA, 0–10 V, 0–5 V, 0.5–4.5 V; digital SSI, RS485, TTL, PROFINET, CAN, EtherCAT; plus START-STOP and PWM. Available outputs per model confirmed at order.
Supply: 24 V, 12 V and 5 V ranges depending on output and model.
Applications
Magnetostrictive Level Transmitter — Industry Applications
Tank gauging where density-independent, absolute measurement or interface detection is required.
⛽
Fuel & Oil Storage Tanks
Absolute inventory level; density-independent reading suits diesel, gasoline and light fuel oil. Flameproof SE-LX20 / SE-LX30 for hazardous-area tank farms.
🛢️
Oil-Water Separators
Dual-float SE-LX20 / SE-LX30 report total product level and the oil-water interface simultaneously — for separators, produced-water systems and slop tanks.
⚗️
Chemical Storage
SGM-LC10 with PP head and PFA float for strong acids and alkalis; stainless SGM-LS10 for solvents. Continuous level for batching and inventory control.
🔋
Energy Storage & Thermal Media
Coolant and thermal-storage tank level for BESS thermal management and thermal energy storage loops, over 4-20mA or RS485 (SGM-LS10, SGM-LK10). See the coolant loop alarm points guide.
🏭
Hydraulic & Lube Reservoirs
Machine-tool and press reservoir level. The slim SGM-LK10 with cable exit integrates directly into OEM power units.
⚡
Transformer & Switchgear Oil
Insulating-oil level in power transformers and tap changers, delivered to the substation controller over 4-20mA or RS485.
💧
Water & Process Tanks
Clean and process water tank gauging where high accuracy and long-term drift-free performance are required over hydrostatic probes.
⚓
Marine & Offshore Tanks
Ballast, fuel and cargo tank level. IP68 protection and stainless construction (SGM-LS10) for salt-laden environments.
Selection Guide
How to Select a Magnetostrictive Level Transmitter — 3 Configuration Paths
Match your measurement task — single level, interface, or a hazardous or corrosive tank — to the right SEGMENsensor series.
📏
Continuous Level Only Most common configuration
Single magnetic float, absolute measurement
SGM-LS10 25–8000 mm, SGM-LK10 25–4000 mm
Output: 4-20mA, 0-10V or RS485/Modbus
Stainless probe, IP68
Best for fuel, chemical, water and reservoir tanks
→ Single-float level version
🛢️
Oil-Water Interface Two-phase media
Dual floats — total level + interface level
Specify both media densities at order (float buoyancy)
SE-LX20 rigid rod or SE-LX30 flexible cable, 200–8000 mm
For separators, tank farms, produced water
Flameproof housing with local display
→ Dual-float interface version
🌡️
Corrosive or Hazardous Tanks Material & approval
SGM-LC10: PP head, PFA float, 25–1000 mm
For strong acids and alkalis
SE-LX10 strap-on for magnetic level indicators
SE-LX series flameproof, 200–8000 mm
SE-LX rod -40~+250℃ (high-temperature version)
→ SGM-LC10 or SE-LX version
Replacing an installed magnetostrictive transmitter?
Send us the tank height, media, output, process connection and register map — our engineers will propose the matching SGM or SE-LX series and quote within 24 hours.
Buyer Questions — RS485 Water Level, 1000 mm Basins, Floats and Samples
Short answers to questions engineers ask before ordering. Values come from the SGM-LS10 and SGM-LK10 datasheets and series pages; anything not listed there is confirmed with the quotation.
Which water level sensor gives continuous RS485 Modbus RTU readings without an atmospheric vent tube?
SGM-LS10 does. It reads the absolute position of a float on a stainless rod rather than hydrostatic pressure, so there is no vent tube to route and no density compensation. It covers 25–8000 mm with ±0.005 mm repeatability, outputs RS485 Modbus RTU (order code R4) and is sealed to IP68; SGM-LK10 offers the same output for 25–4000 mm. For a quote, send tank height, medium, temperature, mounting and quantity.
Is there a 0–1000 mm magnetostrictive level sensor with RS485 Modbus RTU for outdoor water basins?
Yes. SGM-LS10 is orderable at 1000 mm (range code 01000, set in 5 mm steps) with RS485 Modbus RTU output, and its 304 stainless head, tube and flange are sealed to IP68 for indoor or outdoor tanks. Operating temperature is -40 to +85 °C; mounting is M18×1.5 or a customer-specified thread. For a quote, send basin depth, mounting, cable length and quantity.
What float diameter and stilling-tube size does a magnetostrictive level sensor need, and can I get 1–5 samples first?
On SGM-LS10 the float is Ø42 mm on a Ø10 mm rod; on SGM-LK10 it is Ø52 mm on a Ø17 mm rod. Both have a 50 mm top dead zone and about 31 mm bottom dead zone, which varies with the float. Use a stilling well in turbulent tanks; its size is confirmed against the float drawing at quotation. Yes, qualification samples of 1–5 pcs ship in 5–7 working days.
Customization and limits
Item
What can be specified
Limit / not suitable
Measuring range
25–8000 mm (SGM-LS10), 25–4000 mm (SGM-LK10), 25–1000 mm (SGM-LC10), in 5 mm steps
Range excludes the top and bottom dead zones; SE-LX series start at 200 mm
Mounting
M18×1.5 standard on SGM-LS10, or a customer-specified thread (code XX)
Flameproof versions only in SE-LX10 / SE-LX20 / SE-LX30
Output
4–20 mA, 0–20 mA, 0–10 V, 0–5 V (normal or reversed) or RS485 Modbus RTU; customer-specified output (code XX); custom register maps
Interface (two floats) only on SE-LX20 / SE-LX30
Connection
M12 connector (K12) or direct cable 2–99 m (C02–C99), customer-specified cable (suffix X)
—
Dead zones and floats
Customer-specified dead zones (Z9); custom magnets quoted on request
Float must fit the tank opening or stilling well
Medium and temperature
304 stainless (SGM-LS10); PP head and PFA float for acids and alkalis (SGM-LC10)
SGM series -40 to +85 °C; above that, SE-LX high-temperature version to +250 °C; no temperature output
Send these details for a quote
Measuring range or tank / basin height (mm)
Medium and its density (both densities for interface)
Process temperature and tank pressure
Output: 4–20 mA, 0–10 V, RS485 Modbus RTU or 2-wire 4–20 mA + HART
Mounting: thread or flange, stilling well size if used
Cable length or M12 connector
Quantity: samples (1–5 pcs) and estimated annual volume
Application, for example water basin, fuel tank or hydraulic reservoir
How does a magnetostrictive level transmitter work?
A magnetostrictive level transmitter uses a probe (rigid rod or flexible cable) containing a magnetostrictive waveguide and a magnetic float that rides on the liquid surface. A current pulse sent down the waveguide interacts with the float's magnetic field (Wiedemann effect), generating a torsional strain pulse at the exact float position. The transit time of this pulse is converted to an absolute level reading, so no re-zeroing is needed after power loss. SEGMENsensor level series: SGM-LS10, SGM-LC10, SGM-LK10 and the flameproof SE-LX10, SE-LX20 and SE-LX30.
What is the difference between a magnetostrictive level transmitter and a float switch?
A float switch is a point-level device — it only tells you whether the liquid is above or below one fixed point. A magnetostrictive level transmitter provides continuous, absolute level measurement along the full probe length with a 4-20mA, 0-10V or RS485 output, plus interface measurement with two floats on SE-LX20 / SE-LX30. For tank gauging and inventory management magnetostrictive is the preferred technology; for simple high/low alarms, a float switch is more economical.
Can a magnetostrictive level transmitter measure the oil-water interface?
Yes. The flameproof SE-LX20 (rigid rod) and SE-LX30 (flexible cable) take one float for level or two floats for level plus interface. The float field of the ordering code gives the number of floats and the liquid densities, for example 2F08F11 for an interface between liquids of density 0.8 and 1.1. Specify both media densities at order so we can select the correct floats.
What measuring length and accuracy are available?
Measuring range per series datasheet: SGM-LS10 25–8000 mm, SGM-LC10 25–1000 mm, SGM-LK10 25–4000 mm, SE-LX10 / SE-LX20 / SE-LX30 200–8000 mm. Repeatability is ±0.005 mm on SGM-LS10 and SGM-LK10, <±0.001% FS (min ±10 µm) on SGM-LC10, and ±1 mm or ±0.1 mm on the SE-LX series (resolution 1 mm or 0.1 mm). Confirm your tank height and mounting so we can size the probe and inactive zones correctly.
Does it measure temperature as well as level?
No. The SGM and SE-LX level series measure level (and interface with two floats on SE-LX20 / SE-LX30); temperature measurement is not part of their datasheets. Use a separate temperature sensor where volume correction or temperature monitoring is needed. The SE-LX measuring rod is rated -40~+85℃, or -40~+250℃ in the high-temperature version.
What output signals and protocols are supported?
SGM-LS10, SGM-LC10 and SGM-LK10: 4-20mA, 0-20mA, 0-10V, 0-5V and RS485 Modbus RTU. SE-LX10, SE-LX20 and SE-LX30: 2-wire 4-20mA + HART (parameters settable with a HART handheld communicator), 4-wire 4-20mA or 0-10V, and RS485 Modbus RTU, with a local display. 4-20mA suits direct connection to PLC / DCS analog inputs; RS485 Modbus RTU suits multi-drop networks. Further interfaces are available per model: 2-wire 4–20 mA + HART, 0.5–4.5 V, TTL, PROFINET, CAN, EtherCAT, START-STOP and PWM; available outputs are confirmed at order.
Is it suitable for hazardous-area fuel and chemical tanks?
Yes. The SE-LX10 (strap-on), SE-LX20 (rigid rod) and SE-LX30 (flexible cable) have a flameproof housing with local display for hazardous areas such as petroleum and chemical plants. Confirm the required gas group and temperature class when you enquire — the certificate and marking for the specified model are confirmed with the order. For corrosive media choose SGM-LC10 (PP / PFA); stainless versions are SGM-LS10 and SGM-LK10.
What is the MOQ, lead time, and can you supply OEM / private-label units?
Qualification samples are 1–5 pcs; samples of 1–5 pcs ship in 5–7 working days. Lead time depends on probe length and options and is confirmed with the quotation. SEGMENsensor is a factory-direct OEM manufacturer in Shenzhen (registration 91440300MAEUXXQU04) and supplies private-label housings, custom flanges/threads, custom register maps, and OEM datasheets. CE and RoHS documentation is provided with each order; calibration and material certificates are available on request.
Ready to Source Magnetostrictive Level Transmitters from a China OEM Factory?
Specify your tank height, media, interface needs, and output — we'll send a quote and datasheet within 24 hours.
