Magnetostrictive Level Transmitters

The LTM series Magnetostrictive level transmitters offer highly accurate and precise liquid level measurement with a variety of configuration options. The LTM may be utilized as a direct insertion transmitter or externally mounted to a magnetic level gauge for non-invasive level control.

The LTM sensor probe with magnetic float(s) is inserted directly into a tank. As the float rises or falls with the fluid, the transmitter provides level output. LTM transmitters are available with two-wire loop powered 4-20mA signal output and HART.

The LTM level transmitter operation is based on the principle of Magnetostrictive technology. To explain briefly, the sensor consists of an alloy wire with specific magnetic characteristics called the wave guide. The wave guide is housed within a stainless steel tube, creating the probe assembly. The transmitter electronically generates a high current pulse which is transmitted down the wave guide, producing a circular magnetic field as it travels down the wire. Another magnetic field is generated on the wave guide by the permanent magnet in the float along the length of the probe. When the pulse field interfaces with float magnetic field, a torsional force is produced, twisting the wire and producing a torsional wave. The time of flight of the torsional wave is measured and the distance to the float is easily calculated.

Other configurations include remote mounted electronics for easy access or high temperature applications. Sensor probes are available in a variety of materials, including stainless steel and exotic alloys (Monel, Hastelloy, etc.). Sensor probes may also be electro polished for sanitary applications. All LTM transmitters feature explosion-proof, dual compartment enclosures with integral displays.

The plug-and-play electronics allow easy upgrades from HART to Fieldbus without replacing the sensor probe. LTM transmitters offer the latest and most advanced software features on the market, introducing the only registered HART DD compliant to IEC 61804-2 and compliance certified to HART 7.


  • Position Sensing
  • Sanitary Service
  • Valve Positioning
  • Inventory Control
  • Corrosive Process
  • Underground Tanks
  • Primary Level/Interface
  • Process Temperature and Level


  • Marine
  • Coatings
  • Oil and Gas
  • Petrochemicals
  • Pharmaceutical
  • Power Industries
  • Food and Beverage

Electronic Specifications

Supply Voltage:13 to 36 VDC

Repeatability: .005% of full scale or .010 in., whichever is greater

Non-Linearity: .01% of full scale or .030 in., whichever is greater

Level Sensor Accuracy: .01% of full scale or .030 in., whichever is greater

Analog Output: (1) 4/20mA primary level

Resolution: .025% of full scale

Output: Primary level, (1) 4/20mA optional digital outputs via HART for Temperature or interface detection

Calibration: Zero and span field adjust with push buttons or HART; Secondary level is auto-detect; temperature is configured Via HART or AMS only

Diagnostics: On-board diagnostics for troubleshooting

Dampening: 1 to 25 seconds (field adjustable via display)

Electronics Operating Temperature: 1 to 25 seconds (field adjustable via display)

Housing: Explosion proof, dual compartment, 1/2in NPT, epoxy coated Aluminum; stainless steel optional

Polarity Protection: Diode in series with the loop

Approvals: CSA-USA Explosion Proof Class I, Div. I Groups B, C, D, E, F, G Class III, NEMA 4X, IP66

Humidity Limits: SAMA PMC 31.1-5.2

Vibration Limits: SAMA PMC 31.1-5.3

RFI Limits: SAMA PMC 31.1-20 to 1,000 MHz up to 30V/m

Transmitter Sensor Tube:

Material: 316 Stainless Steel standard, Optional Hastelloy, Monel, Kynar sleeve

Operating Temperature:-50 to 300 F (-50 to 150 C)

Max. Pressure:2000 PSI @ 300 F

Range: 12 inches to 30 ft.

Specifications subject to change without notice

LTM Order Information

Direct Insertion Type
Model # (Example)Probe Material
K=Kynar Sleeve
Mounting Connection
3=3/4"NPT (Standard)
Min. Operating S.G.Max. Operating Temp.(F or C)Max. Operating Press. (PSI)Measuring Length (Inches)Options
LTM 350S 3 3 0.64 150F F 300 30.00 RM10
Gauge Mount
Model # (Example)Measuring LengthOptions
LTM 250 30.00 RM10
Model # (Example)*

250 Single Output Analog, Alum. Housing
251 Single Output Analog, SST Housing
350 HART* (3 Variables), Alum. Housing
351 HART* (3 Variables), SST Housing


Temp = Temp Output (Digital)
Dual = Dual Level Outputs
INT = Interface (Specify both S.G.’s)
SW = Stilling Well (Specify size; required over 10 Ft)
3A = 3A Sanitary Application
RM = Remote Electronics (Specify cable length in FT.)

Options* (Gauge Mount)

RM = Remote Mount Electronics (Specify cable length in FT.) (Mounting elbow standard)


LTM Series Magnetostrictive Level Transmitter

magnetostrictive level transmitter