The development of computerized layer winding and improved microprocessing has greatly reduced the body length of the linear position sensor compared to its measurable stroke length. The LVDT linear position sensor has an improved stroke length ratio (now up to 80%) and is a viable position measuring device for hydraulic cylinder positioning.

The role of cylinders in most hydraulic applications is to move "something" on off-road vehicles, such as valves, aircraft rudders or booms or shovel. In these applications, the control system requires a feedback device that tells it how far the cylinder or actuator has moved to ensure proper operation. This is where the linear position sensor comes in. The LVDT is mounted inside or outside the cylinder, tracks the movement of the actuator and electronically reports the data to the control system, which monitors and provides operational condition alarms.

Shorter stroke length makes LVDT linear position sensor ideal for hydraulic cylinder applications

For example, if the pilot wants to turn the airplane, he will move the joystick. The aircraft's control system detected that he had moved the joystick and sent a signal to the rudder actuator to move the rudder. If the system is unable to know how far the actuator has moved through the position feedback provided by the LVDT linear position sensor, the aircraft may turn too much or not enough.

The second example is the robot arm. In this case, assume that the robot arm will move to pick up a piece of glass. If the control system does not know when to stop the arm by receiving position feedback from the LVDT linear position sensor, the hydraulic cylinder can drive the arm directly through the glass sheet.

Care should be taken when selecting the appropriate LVDT linear position sensor for your application. Although the miniature LVDT is suitable for high-response dynamic measurements, the sealed LVDT is ideally suited to withstand high pressure washes, dust and, in some cases, submerged environments.