Strip width measurement on an Edge milling machine

[Prince]

Newly I am trying to improve an "strip edge milling" machine. as you know better this kind of machine mills the steel strip edges on either side for a better welding result in Pipe making .At the first glance the machine have a mechanical transducer in order to measure strip edges and calculate the width of the strip. I want to change the sensors into no contact type. I checked Siemens and they offer 3RG70561 family. Its range and resolution were acceptable the only problem I've found about it was this small notification in the catalog that their working distance must be 65±1 mm. here I think that I will have ±5mm vibration

This Family are Laser sensors so why must their distance to the strip be so important?
Can anybody suggest me another sensor not sensible to vibrations ?

 

[bernie_carlton]

I think the specifications are saying that the sensor should be placed at 65 mm nominally. It appears to give a usable output from 45 to 85 mm (a 40 mm range). So its analog output will be at one extreme at 45 mm and at the other extreme at 85 mm.

The sensor will probably work correctly but it will indicate the 5mm variance. You will have to take that into account in your program. You may need to program a suitable filter.