Analysis of basic position loop control systems

The author discusses the basics of loop position and the tension variation in a product caused by the loop. He covers the basic catenary, position regulator gain, weighted dancer loops with and without a counterweight, and other possible approaches to loop control. It is noted that it is known that the tension variations on the material being processed on a continuous process line can affect the product quality. It can be seen from the examples discussed that it is not obvious what the real tension variation may be for a particular loop design. The present work is intended as a guideline to give the design engineer a good starting point to make sure product uniformity is taken into account in specific designs.<>