Hi-Endurance Switching, Sensing
& Linear Position Sensors

Comparison of Hydraulic Cylinder Position Sensing Technologies.

For over a decade the same basic technologies have dominated the landscape of hydraulic cylinder position sensing for harsh environments. Recently a hybrid solution developed by Control Products Inc of East Hanover NJ, has solidly entered the field providing increased reliability and robustness in harsh environmental deployments, and ease of retrofit for the field replacement of existing sensor types.

A comparison of basic sensor types with their relative strengths and weaknesses shows how this new sensor compares to the major Linear Position Sensor Technologies

Properties Poten-tiometer Magneto-strictive LVDT Draw Wire(Optical Encoder) OpticalEncoder CPI SL-Series
Electronics Complexity Low Moderate Moderate High High Moderate
Non-Contacting No Yes Yes Yes Yes Yes
Accuracy Fair Excellent Excellent Very Good Excellent Very Good
Resolution Fair Excellent Excellent Excellent Excellent Excellent
Temp. Range Fair Very Good Excellent Excellent Excellent Excellent
Vibration Immunity Fair Good Excellent Fair Fair Excellent
Magnetic Field Immunity Excellent FAIR Very Good Very Good Very Good Very Good
Temp Range Fair Good Excellent Excellent Excellent Excellent
Linearity Moderate Very Good Good Very Good Very Good Good
Cost Low High Moderate Moderate High High
Max Stroke Length 20” 120” 20” 120” 60 in 275”
Telescoping Cylinders No No No Yes No Yes

A Few additional conclusions can be drawn from the table above and a general survey of the field performance of these position sensors.

  • Optical Sensors are the most accurate but can be expensive, require sensitive and complex electronics and are completely unsuitable for high vibration outdoor environments.
  • Magnetostrictive sensors require core drilling of the piston rod to insert.  Every piston length requires a different length sensor rod to be inserted. The longer the rod, the more sensitive it is to vibration, warping, and breakage.
  • Magnetostrictive sensors have poor EMI immunity, affecting accuracy.
  • Only draw wire sensors have characteristics appropriate to telescoping cylinders.
  • CPI sensors boast the longest stroke measurement lengths in this class.
  • By combining noise immune LVDT technology, with the flexible usage configurations inherent to field proven draw wire technology, CPI SL series sensors represent the best set of tradeoffs for robust environmental requirements.

If you have additional questions about our SL series linear position sensor technology, call our team today.



Make The "Switch" to CPI

If your momentary switch application demands high performance, we think you should demand CPI. Please call us today to speak with our engineering team about your needs.

(973) 887-9400