A Scanning Contact Sensor for Sheet Processes

The NDC Infrared Model 360 Eddy Current scanning caliper sensor is designed for on-line thickness measurement of continuous web processes. The upper sensor head, containing a precise Variable Impedance Transducer (VIT), rides on the surface of the product and senses the distance to the lower reference head. The measurement is always representative of actual product thickness and inherently insensitive to product composition, color or density changes.

The NDC Infrared Model OSA family of O-Frame scanners provides the ultimate in high speed traversing for the Model 360 measurement sensors. Scanners are compact and offered for a full range of web widths.

Theory of Operation
The Model 360 sensor is based on Eddy Current Technology employing a VIT. The product to be measured rides between the "active" upper head and the lower reference head. A magnetic field is created between the upper and lower sensor heads, which in turn creates a voltage that precisely relates to the distance between the two heads. As the material to be measured lifts the upper active sensor the VIT in the upper sensor measures the change in sensor separation. This is connected to the local demodulator electronics unit that produces a linear voltage output proportional to the sensor separation. This voltage is then converted into a differential frequency signal proportional to voltage. This conversion is done in the sensor head demodulator to insure a noise free signal and is then sent on to the gauge electronics for processing in the system display and control console.

Features and Benefits

• Absolute thickness measurement
• Non-Nuclear sensor technology
• Measurement range from 20 - 200 mil (0.5 - 5mm)
• Long-term stability and repeatability
• Unaffected by changes in product composition, density or color
• Compact, rugged and easily maintained
• Unique lower reference head design eliminates errors relating to product listing

Click for Technical Specifications

Korins Co.,Ltd.
Rm301, #24-2, Youido-Dong, Youngdungpo-Ku, Seoul, Korea
Tel. : (02)780-4848 Fax.:(02)780-1244, 786-1244

sales@korins.com