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Potentiometer vs LDT in the printing industry

We often hear, "I am looking for a budget-friendly position sensor for our web printing machine to monitor the dancers. What does a potentiometer cost?" It is essential to underline that the cost of potentiometers can be budget-friendly when you buy the potentiometer, but we calculate the cost of position sensors also potentiometer cost with a lifetime perspective; with this perspective, linear position sensors, such as linear displacement transducers, are, in fact, the cheap solution.

Linear Displacement Transducers, LDTs, have proven very successful in the printing industry. Monitoring dancer and accumulator positioning on continuous web printing demands precision. Failure may cause breakage of the web, working hours wasted and pressure on workflow and deadlines.

Monitoring the dancers on web printing machines is often performed by potentiometers. The potentiometer cost is low, but they may from time to time provide certain issues which, in general, can be avoided by using LDT. The movement of a potentiometer is limited whereas the linear displacement transducer can be delivered on customized sizes matching the individual machine. A more important issue is that these may get stuck in a position if held for a long time, and that potentiometers are subject to wear. The contact free construction and the electromagnetic technology of LDTs, such as Gemco 955 eBrik, secures the user high precision and reliable monitoring as well as virtually no wear even in the long run.  

Potentiometer  Linear Displacement Transducer

The experience from the printing industry clearly shows that the accuracy, stability and longevity of the linear displacement transducers provides outstanding production security. 

Is it and expensive solution? No, an LDT is in fact a budget-friendly solution, the linear displacement transducer may have a higher price initially, but the longevity of the linear displacement transducer brings a lower cost in the long run compared to, for instance, the potentiometer cost. If we add to the equation the lower risk of breaking the web while printing, the benefits are just even greater.  

Based on feedback from the printing industry AMETEK Factory Automation have created 2 application notes that investigates the differences of the dancer and accumulator monitoring instruments. 
Application Note: Magnetostrictive Control of Dancers on Rotation Press

Application Note: Magnetostrictive Control of Rotation Press Accumulators