Linear Position Sensor Technology Choices

There are a number of technologies to choose from when considering the implementation of a linear position sensor.  As CPI's own sensors focus on the needs of hydraulic cylinder and hydraulic accumulator designers, it is instructive to review the various technologies being used in this market and the relative tradeoff's of each, as compared to CPI's LVDT based Linear Position Sensors.

Potentiometer based position sensing

Use of a variable resistor attached mechanically to a slider on


CPI Linear Position Sensor Applications

Since we introduced our first LVDT based position sensors back in 1997, we’ve learned a lot about how to refine and extend this technology into some amazing industrial applications. Originally developed for the mobile hydraulics market, CPI sensors have evolved to find uses in many different industries where reliable operation, long stroke lengths and design flexibility are primary requirements. Here are just a few of the many places our unique LVDT sensor design has been


Applying Smart Hydraulic Cylinders

What is a Smart (Hydraulic) Cylinder?

Smart hydraulic cylinders gain their name from the fact that highly accurate position sensing electronics are integrated with the hydraulics in a single actuator.  Thus these cylinders are “smart” about understanding cylinder position allowing robust position information to be fed to more complex feedback systems.

CPI Linear Transducer Usage In The SeaSLICE

CPI smart cylinder for rudder control on SeaSLICEEnter the Lockheed Martin “SeaSLICE” technology, a


LVDT Based Position Sensors Offer Greater Longevity In Harsh Environments

Accurate sensing of linear position in hydraulic cylinders takes on more complex design considerations when targeting applications where a rugged outdoor environment is the operational norm. Environmental considerations include:

  1. Heat – Not just ambient temperatures but the temperature of hydraulic fluid rises with continued operation and can increase the effective operating temperature range.
  2. Vibration – Applications for hydraulic cylinders in heavy duty construction equipment, drilling and, Mining equipment, etc., present severe challenges for certain types of sensors, most


Long Stroke Hydraulic Cylinders Part 2 – Replacing Failed Rod-Type Sensors.

Rod based magnetostrictive position sensors are historically one of the primary types of feedback sensors used on hydraulic or pneumatic cylinders where high accuracy was of primary concern.  The sensor (often called an “LDT” or “MLDT”) incorporates a stainless steel tubular probe (ie. “the Rod”) and is surrounded by a short toroidal magnet installed in a counterbore in the piston. Magnetostrictive sensors can consume a fair amount of power and are not the most mechanically


LVDT Based Linear Position Sensors

Engineers and heavy equipment operators responsible for the maintenance of large scale hydraulics in the field, know what's at stake when these systems fail.  Costs to repair and impact to production represent a huge operational risk that can quickly have large financial repercussions.  These risks to equipment and productivity are a key hydraulic cylinder design consideration and steps are typically taken to minimize potential failure modes at every step of the engineering process. Last year, CPI