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sub-sea submersible LVDT position sensor

Submersible LVDT Position Transmitters

Environmental Data
Operating Pressure 5000 PSIG*
Proof Pressure 7500 PSIG*
Operating Temperature -30 °C to +80°C
-20 °F to +175 °F
Temperature Sensitivity 0.027%/°C (max.)
0.015%/°F (max.)
Vibration Tolerance 20 g to 2 kHz
Shock Survival 100 g, 11 ms
Ingress Protection IP69K*
*with appropriate Seacon-Brantner mating connector
  • Off-shore drilling platforms
  • Pipeline monitoring
  • Choke valves
  • ROV and exploration
  • Mooring cables
  • Extensometers
  • Long term reliability (20+ years)
  • Inconel construction standard
  • High pressure applications (to 5,000 psi)
  • 4-20mA two-wire, loop-powered I/O
  • Non-linearity of ±0.10% of FRO or better
  • High pressure Seacon-Brantner subsea connector standard
  • Welded connector also available

Due to their extraordinary repeatability despite variations in pressure and temperature, Macro Sensors SSIR 937 Series submersible LVDTs are ideal for incorporation into a wide variety of subsea measurement systems. These rugged, .94 inch [nom.] (24 mm) diameter sensors are available in standard ranges of 2.00 inches (50 mm), 3.00 inches (75 mm) or 4.00 inches (100 mm), although other ranges are available at special request.

To withstand deepsea environments with external pressures to 5000 psi, SSIR Series LVDTs are constructed of Inconel. Inconel enhances the already high-reliability of the LVDT assembly, ensuring that it can meet service life requirements of at least 20 years, even if the device is fully exposed to seawater.

SSIR Series LVDTs also resolve the problem of getting a signal back to the surface, even at great water depths. To minimize the number of pressure sealed I/O connections and to minimize noise over long transmission lines, a 4-20 mA two-wire, loop-powered I/O is utilized. Offsets can be easily made in the data acquisition system on the platform above. Electrical termination is through a high pressure Seacon-Brantner subsea connector.

Some typical applications include monitoring structural movement for long-term FEA (Finite Element Analysis) of pipelines, derricks, moorings and other critical high stress members on offshore oil platforms. SSIR Series LVDTs are designed for use in either pressure-balanced, oilfilled containers or directly in seawater.

Linearity Error ≤ ±0.10% of Full Range
Repeatability Error ≤ 0.01% of Full Range
Electrical Data
Output 4-20mA
Input 12-28VDC
Loop Resistance 50 Ω (min.) see graph at right
Current Consumption -
Output Noise & Ripple <10 μArms
Bandwidth; Electrical (-3dB): DC to 50 Hz
Connector Wiring  
Pin A Loop +
Pin B Loop -
Pin C Do Not Connect
Pin D Do Not Connect
XSEE-6-BCR Connector
Pin E Not Connected
Pin F Case Ground
Electrical Connection
SSI (4-20 mA)
Loop Resistance (Max.) vs. Loop Supply Voltage
SSIR 937 Series
SSIR 937 Series Dimensional Data
SSIR 937 Series Ordering Info
Parameter Unit of Measure SSIR 937-2000 SSIR 937-3000 SSIR 937-4000
Range inches 2.00 3.00 4.00
mm 50.8 76.2 101.6
Scale Factor mA/inch 8.0 5.33 4.0
mA/mm 0.31 0.21 0.16
Body Length "A" inches 8.80 11.95 11.95
mm 223.5 303.5 303.5
Core Length "B" inches 4.36 6.33 6.33
mm 111.0 161.0 161.0
Core Position "C"
(at 12 mA)
inches 1.70 2.70 2.70
mm 43.2 68.6 68.6
Stroke "S"
(SI = Insert Stroke)
(SE = Extend Stroke)
inches 1.00 1.50 2.00
mm 25.4 38.1 50.8
Weight - Body ounces 30 40 40
grams 850 1130 1130
Weight - Core ounces 0.50 0.65 0.65
grams 14 18 18
SSI 937 Series Dimensional Drawing

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