Laser Caliper Sensors NDC Infrared Engineering logo

Laser Caliper Sensors - Models 170 and 172

A new and innovative sensor for highly accurate, non-contact measurement of web thickness. Features include dynamic compensation for changes in measurement gap or roll runout.

Features
  • High Precision
  • Non-Contacting Measurement
  • Unaffected by Product Density
  • Insensitive to Changes in Color or Texture
  • Dynamic Compensation for Change in Gap or Roll Run-Out
  • Compact, Rugged and Easily Maintained

Description
Laser

The NDC Infrared Engineering Model 170 series of laser caliper sensors is designed for on-line thickness measurement of continuous web products. The sensors are available in different configurations to enable thickness measurement of a variety of products, from one or both sides of the web. Measurement is made without contacting the web in any way

The Model 170 sensors are designed to continuously measure true product thickness without being affected by changes in the density of the product. The sensor utilizes a proprietary laser measurement system that is insensitive to changes in color or surface reflectivity of the web. A precision electromagnetic radio frequency sensor is incorporated with the laser to immediately sense and compensate for any changes that may occur in the measurement gap or the distance to a roll,

NDC Infrared  employs a compact and rugged design to insure suitability to the harshest online conditions. The sensors can be mounted in a fixed position or on NDC Infrared's family of scanning frames.

Dual Sided Measurement
Model 172
 O-Frame Scanner
172

Theory of Operation

Single Sided Measurement
Model 170
Traverse Frame Scanner
170

The measurement technique is distance triangulation based on the output of a laser diode, a system of lenses and an optical detector. A coherent beam of near infrared light is reflected off the surface of the product. The reflected beam is focused onto a linear optical sensor that very precisely measures the position of the beam. For a web distance I the beam will be focused at position 1 on the detector. When the web is at distance 2, the beam will be focused at position 2. The laser is located in the center of the inductive coil of a radio frequency proximity sensor. The proximity sensor measures changes in the distance between top and bottom lasers or between a single-sided laser and a reference roll. Compensation for such changes is effected in real time.

Click for Technical Specifications
theory

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