The width of a paper reel, ranging from 1500mm to 300 mm, need to be accurately measure. The accuracy level is to be 1 mm or less. A contact type or non contact type measuring technique can be suggested.
You can use as well a sensor in the top of the reel and check the value of the distance, because when the reel are growing the distance is less, and you can put you limits I mean yours MAx and mins or an analog value as well. I recommend you the CCD Laser Displacement Sensor from Keyence i don't remenber the series I think is the LK series.
Best Regards
Luis Cardona
Control Systems Eng.
Ethicon Endo-Surgery Inc.
An opposing pair of laser distance measuring meters mounted either side of the reel might achieve that accuracy. Try Sick. Alternatively, an opposing pair of optical proximity sensors mounted on linear positioners controlled to track the edge position would probably work. Try Banner or Omron. In my experience the focussed sensors have repeatabilities much less than 1mm.
A laser line read by a CCD camera will work as long as the hieght remains constant between the strip and the camera. An other way to measure with a CCd camera would to have a back light and measure the edges. There are a several systems available on the market.
Try the link of some vendors that I have had good luck with:
These guys build heavy duty systems for steel mills, but they would probably be able to cheapen their product for paper. I wouldn't bother with any kind of contact measurment unless you plan on baby sitting the system.
