Al, this is an interesting approach. I looked at their site, and the pdf. It is not really clear how they do it. Are there multiple independent controllers or is one controller programmed to treat each zone independently?
Hello Naperlou, I am in the development department of Bosch Rexroth where this feature is programmed.
The architecture is that there are several controllers: One controller for each tension zone which can be tuned independently. The outputs of these several controllers are combined together within a "decoupling network" in order to achieve decoupling of the tension zones. With that every controller can control "it's own" tension zone independently, i.e. without affecting the tension in all other zones.
This leads to a much more robust system, i.e. a lower tendency for oscillations. The increased robustness can also be used to use "stronger" tension control parameters and therefore achieve a higher dynamic leading to a higher tension accuracy leading to a higher register accuracy. In some applications the only way to get a stable tension is using this decoupling network feature, or to get a tremendous waste which is quite expensive in printed electronic applications. Estimating the yearly waste costs you get when you produce e.g. additional 60-100 feet waste at every machine start is astonishing.
Remark: "A perfect tension is a base – or better – THE base for a perfect register."
The effect is independent of the web speed, i.e. it is present as well in digital printing applications as in printed electronic applications. One of the differences between these two is that in digital printing applications (e.g. inkjet) the printing unit does not affect (= transport) the web so that web tension variations directly influence the register and therefore the decoupling is recommended resp. needed. Printed electronic applications have higher accuracy demands so that best web tension stability is the measure.
See also: http://www.drive-and-control.com/technology/printing-smart-objects
Feel free to contact our colleagues in the US to get more information about our innovative tension control solution.
Naperlou, Many applications can use a single machine controller with groups of axes (forming tension control zone) linked together in software using a combination of electronic gearing, electronic camming and inputs from feedback devices including high speed programmable limit switches, sensors and/or load cells. Each of the zones use software to achieve digital tension control within a specific zone (using distributed processing by running motion algorithms in the servo drives) but each zone is also melded into the overall process as well. Higher performance systems in this area are examples of very sophisticated adaptive control. Hope that helps.
Most machine design engineers will survey existing component manufacturers for standard linear guide products, limiting what they can do with their designs. Using extruded aluminum profile guides can customize machine designs while shrinking the bill of materials.
Weaned on the relatively effortless connectivity of today’s massive variety of consumer electronic products, automation users in the IIoT will likely not tolerate too many competing, piecemeal standards for long. And the Industrial Internet Consortium is trying to preempt history.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.