Linear Position Sensors

SL2000 with cable pulled, iso

Environmentally Hardened, Non-Contacting Draw Wire Position Sensors
Accurately Measure Stroke Lengths from 1 to 30 meters.

  • For Hydraulic Cylinder and Accumulators, or Standalone.
  • Designed for Harsh Duty or Subsea Environments
  • Full Intrinsic Safety Ratings Available.

 

Unique in the industry are CPI’s SL series of draw wire linear position sensors.  These products leave traditional notions of draw wire sensors behind, with their advanced metallurgical design, patented linear to rotary to linear conversion, and hardened absolute measurement technology featuring either short magnetostrictive, or LVDT based transducers.

  SL2000-6000 products combine two proven technologies into a sensor system that can be deployed in subsea applications and are available with virtually any intrinsic safety rating for topside hazardous locations as well. Our advanced harsh duty draw wire mechanisms work together with short probe magnetostrictive transducers to provide a solution to long stroke, harsh duty hydraulic cylinder piston position measurement that is better in every way than the sum of its parts.

Products

SL2000 10M

Fully IS Safety Rated Fully Subsea Rated Internal/External mounting High Precision SEE PRODUCT

SL4000 12M

Fully IS Safety Rated Fully Subsea Rated Internal/External mounting High Precision SEE PRODUCT

SL5000 14M

Fully IS Safety Rated Fully Subsea Rated Internal/External mounting High Precision SEE PRODUCT

SL6000 30M

Fully IS Safety Rated Fully Subsea Rated Internal/External mounting High Precision SEE PRODUCT

SL1390 1M

Fully IS Safety Rated Fully Subsea Rated Internal/External mounting High Precision SEE PRODUCT

SL0390 1M

Fully IS Safety Rated Fully Subsea Rated Internal/External mounting High Precision SEE PRODUCT

Markets

Hydraulic Cylinder/
Accumulator

High Power Hydraulics
In harsh duty outdoor or subsea applications using long stroke hydraulics, CPI SL series hardened draw-wire sensors are often the only option.

Construction
Vehicles

Industrial/Commercial
Elevator telescoping cylinders, paper processing tensioner cylinders, piston accumulator sensors

Offshore
Drilling

Oil Exploration/Recovery
Rig raiser hydraulics, heave compensation, blow-out preventer, valve control, subsea accumulator charge sensing

Mining
Equipment

Mining
Hydraulic push beam system (long-stroke cylinder), intrinsic-safety rated sensors, draw wire systems for harsh environments

Military Vehicles/
Boats

Military 
Hydraulic push beam system (long-stroke cylinder), intrinsic-safety rated sensors, draw wire systems for harsh environments

Dams and Marine
Applications

Dams and Marine Applications
Dam construction, dredging hydraulics, rudder position controls, marine depth detection, subsea charge sensing

Monitoring absolute piston position in hydraulic accumulators has been a nightmare for designers, as traditional rod-type solutions require an additional dynamic seal around the probe (through the center of the piston). Fabrication challenges, additional seal leaks, and sagging probes in long-stroke applications are among the pitfalls of this approach. The CPI draw wire sensor overcomes all of these issues, offering internal mount as well as external mount configurations which minimize impact on accumulator design.

CPI Sensors represent the only internal sensor technology in the world suitable for long-stroke telescoping cylinders. We offer various installation options, including completely internal units suitable for dual-clevis designs. And, with the integration of magnetostrictive core sensors, all hazardous environment capabilities are at your disposal


The CPI SL Series Safety Rated Linear Position Sensors

Designed especially for the needs of the Oil & Gas Industry, the CPI sensor system provides one uniform solution to position measurement both on the drilling platform and at the well head. Systems such as Blow-Out Preventers, or Heave Compensation Systems that use hydraulic cylinders or accumulators will find  our Safety Rated sensors the perfect solutions to reliability and durability concerns both above and below the surface. Since magnetostrictive sensors are available in intrinsically safe, as well as explosion proof variations, with various ATEX, SIL, and IECeX ratings for virtually any hazardous environment, these capabilities translate directly to our SL Series draw wire products.

The Best Sensor for Hydraulic Piston Accumulators

Monitoring absolute piston position in hydraulic accumulators has been a nightmare for designers, as traditional rod-type solutions require an additional dynamic seal around the probe (through the center of the piston). Fabrication challenges, additional seal leaks, and sagging probes in long-stroke applications are among the pitfalls of this approach. The CPI draw wire sensor overcomes all of these issues, offering internal mount as well as external mount configurations which minimize impact on accumulator design.

The Only Internal Sensor for Telescoping Cylinders (That actually Works)

CPI Sensors represent the only internal sensor technology in the world suitable for long-stroke telescoping cylinders. We offer various installation options, including completely internal units suitable for dual-clevis designs. And, with the integration of magnetostrictive core sensors, all hazardous environment capabilities are at your disposal.

Checkout our SL Series FAQs

Hydraulic Cylinder Position Sensors

Harsh Duty Linear Position Sensors

Hydraulic Accumulator Charge Sensors & Long-Stroke Hydraulics

Product:  SL0390, SL1390, SL2000Product: SL1390, SL2000Product: SL2000,  SL4000, SL5000 SL6000
CPI Linear draw wire position sensorLinear Position sensor, Draw Wire Sensor, String PotSL6000 Long Stroke Linear Position Sensor for underwater or subsea hydraulic cylinder use
Technology: Non-Contacting LVDT & magnetostrictive based.Technology: Non-Contacting LVDT & magnetostrictive based.Technology: Non-Contacting LVDT & magnetostrictive based.
Mounting: Internal/ExternalMounting: InternalMounting: Internal/External
Stroke: 1M to 30MStroke: 1M to 30MStroke: to 10M
Operating Temp:
-40F to 250F
Operating Temp:
-40F to 250F
Operating Temp:
-40F to 250F

Additionally CPI makes a line of linear position sensors designed to drop in replace magnetostrictive sensors in any hydraulic cylinder application. Read about our Magnetostrictive position sensor replacement series here.

Hardened Draw Wire Sensor Meets Unique Transducer Technology

Draw Wire Linear Position Sensor uses magnetostrictive transducer

The CPI SL2000 (Pictured without internal protective housing) can support stroke lengths of 15M and survive the harshest underwater environments.

CPI sensors are a subset of a class of sensors historically referred to as draw-wire or “string-pot” sensors, designs that many design engineers are familiar with. However, that is where the historical similarity ends. In CPI’s completely new approach to this sensor class, there is no string and there is no pot!  Instead the inherent stability and simplicity of this proven class of sensors is improved from head to toe through material science engineering with a patented linear to rotary to linear mechanism at its core. By teaming this precise translating spool system with either a short rod magnetostrictive sensor or a Linear Variable Differential Transformer (LVDT), we achieve a 100% non-contacting, highly accurate sensor that outlasts and outperforms all other draw wire and hydraulic sensor technologies in this application space.

The advanced design of the CPI SL series sensor is also a highly accurate solution and versatile solution with numerous advantages over other technologies for long stroke, harsh duty deployment. Click HERE to The Pitfalls of Draw Wire Sensors Overcome by CPI SL Series Sensor Systems.

  1. Non-Contacting Transducer Technology– Our sensor technology employs a unique linear-to-rotary-to-linear measurement system which allows either a short rod magnetostrictive sensor or an LVDT to generate absolute position signals accurate to 1mm over a 10 meter stroke length.
  2. Standard signal conditioning outputs such as CAN Bus, Analog, and Digital.
  3. Our normal operating temperature range is from -40 F to 250F.  This is 1.5 to 2x the operating temperature range of traditional draw wire sensors.
  4. Our sensors can be deployed on the oil or the gas side of an accumulator with no need for a dynamic seal on the piston or core drilling the piston rod.
  5. Our standard sensors can be submerged in water, gray water, sea water, process fluids and other corrosive fluids. Deep submersion units like our SL2000 are also available for subsea applications.
  6. CPI sensors are the only linear position sensors suitable for telescoping hydraulic cylinders
  7. The technology delivers absolute position signals and requires no homing on startup.

Linear Position Sensor Applications

Our LVDT and magnetostrictive -based Linear Position Sensors find applications everywhere from the high temperature environment of a steel mill cauldron control, to the corrosive undersea world of oil exploration; not to mention everywhere in between where harsh environments and maximum durability and reliability are a concern.

  1. Charge Sensing in Hydraulic Accumulators – Sensing charge in hydraulic accumulators is a challenge for other sensor types that invade the piston and require seals that wear out over time. CPI Linear Position Sensors can be easily deployed on the oil side or gas side of the piston accumulator; no dynamic seal or sensor rod tube required!
  2. Smart Hydraulic Cylinders – So called “smart cylinders” encapsulate their position sensing solutions inside the cylinder. Sensors are completely protected, however significant integration challenges are the trade off. CPI sensors are well suited to these designs allowing for easy internal integration. Alternatively, remote location of the spooling and signal conditioning electronics is possible, virtually eliminating cylinder design mods.
  3. Telescoping Hydraulic Cylinders – CPI is the  only linear position sensor that can be installed within telescoping cylinders and one of even fewer such sensors that can make a claim to extreme durability and performance in the tough conditions these cylinders usually find themselves in.
  4. Subsea Hydraulics – Our SL2000-6000 Series sensors are a first choice for serious subsea applications due to their ability to be completely submersed in almost any kind of liquid, deployed to depths of 10,000 feet.
  5. Long Stroke Hydraulic Cylinders – For large, powerful, long stroke cylinders, rod-type sensors become increasingly problematic. The CPI SL2000 is a robust draw wire design able to accurately sense to 1mm over a 10 meter stroke length. A single part number will cover all stroke lengths within the sensor capability.

CPI Linear Position Sensors – A Short History

For 15 years now, CPI linear position sensor technology has marketed and refined its harsh duty draw wire sensor technology to the point where it has gained wide acceptance into hundreds of applications around the world as a robust and cost-effective solution.  In fact, it is often the only real solution to the position sensing challenges of large hydraulics under extreme conditions. Our sensors have been deployed on Navy vehicles, Oil platforms, as valve position feedback, and on huge heavy duty construction vehicles used in mining, and drilling operations. We’re in the oil exploration industry, the construction industry, the mining industry, and the power industry to name a few. Anywhere that uses big hydraulics, in challenging conditions, you’ll find CPI.

 

Contact Our Engineering Sales Team for More Information at (973) 887-9400.