{"id":19263,"date":"2026-06-30T08:27:03","date_gmt":"2026-06-30T06:27:03","guid":{"rendered":"https:\/\/roder.it\/inspection\/speed-and-rotation-in-motion\/"},"modified":"2026-09-22T08:09:21","modified_gmt":"2026-09-22T06:09:21","slug":"speed-and-rotation-in-motion","status":"publish","type":"page","link":"https:\/\/roder.it\/en\/inspection\/speed-and-rotation-in-motion\/","title":{"rendered":"Speed and rotation in motion"},"content":{"rendered":"\n

The speed<\/strong> of a moving material is a central physical quantity in process control: drive synchronisation, cutting to length, metre counting and line regulation all depend on it. In this Inspection<\/em> section we examine the quantity \u201cspeed\u201d in its various forms \u2014 surface, linear, multidimensional \u2014 and the methods for measuring it with non-contact optical speed meters and encoders<\/a>. <\/p>\n\n

Unlike the Technologies<\/a> (theory) and Applications<\/a> (practical cases) sections, here we concentrate on the measured quantity<\/strong>: how it is defined, in which units it is expressed and which instruments determine it accurately.<\/p>\n\n

<\/div>\n\n
\"banner<\/span>
\n

Would you like help choosing the right product ?<\/strong><\/p>\n\n\n\n

\n
Click here !<\/a><\/div>\n<\/div>\n<\/div><\/div>\n\n
<\/div>\n\n

Speed as a process quantity<\/h2>\n\n

Speed expresses the distance covered in unit time and, in the case of materials in continuous production, it is typically measured in metres per second (m\/s) or metres per minute (m\/min). Knowing the real speed of the material is indispensable for many reasons: it makes it possible to derive the length by integration, to synchronise rollers and drives and to keep the process stable. Measuring it accurately, however, is not trivial, above all when the material is hot, shiny or moving at high speed. <\/p>\n\n

\"Optical<\/figure>\n\n

Optical speed meters solve the problem by measuring speed without contact<\/strong>: the VLM500<\/a> using the spatial filter principle (up to 50 m\/s, uncertainty < 0.025 %), the VLM60<\/a> using the correlation method (down to 0 m\/s, bidirectional too).<\/p>\n\n

The different forms of speed<\/h2>\n\n

The speed of a material can be described in different ways depending on the application. Surface and linear speed<\/a> concerns the running of the material along the line; material speed and length<\/a> links speed to the length produced; multidimensional speed<\/a> takes into account movement in several directions (x and y) with direction recognition. Each of these forms is examined in a dedicated page. <\/p>\n\n

Why measure speed optically<\/h2>\n\n