View Comments: Newest First|Oldest First|Threaded View
User Rank
Re: How do they do it?
sschu   10/22/2013 9:59:10 PM
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.

User Rank
Digital Tension Control
apresher   10/4/2013 9:53:57 AM
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.

User Rank
How do they do it?
naperlou   10/4/2013 9:41:50 AM
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?

Partner Zone
Latest Analysis
Check out these gifts that will make you the hero of your Secret Santa party.
Voting has closed on our 2015 Gadget Freak of the Year contest, but it is not game over yet for two competing projects.
Independent science safety company Underwriters Laboratories is providing new guidance for manufacturers about how to follow the latest IEC standards for implementing safety features in programmable logic controllers.
Automakers are adding greater digital capabilities to their design and engineering activities to promote collaboration among staff and suppliers, input consumer feedback, shorten product development cycles, and meet evolving end-use needs.
Design News caught up recently with Punya Prakash, the 2013 recipient of our Rising Engineering Star award. What has she been up to?
Design News Webinar Series
11/10/2015 11:00 a.m. California / 2:00 p.m. New York
10/29/2015 11:00 a.m. California / 2:00 p.m. New York
10/20/2015 8:00 a.m. California / 11:00 a.m. New York
12/2/2015 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Jul 6 - 10, Building Raspberry Pi Controllers with Python
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6 |  7

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.
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2015 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service