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October 16, 2012
News - Engineering Roundtable - …
about 2 years ago
I don't want to sound like I'm ragging on you, because that's a neat rig. However a big part of my job is programming winders for sheet steel up to 3/4" thick, so here's a few concepts you might be interested in - "Dancers" and "Torque Control." A dancer is a feedback mechanism that monitors the tension of your web. I typically use inclinometers, but you can use encoders, reactors, differential transformers, or just potentiometers. Let the dancer "ride" on the web, and then use it's feedback as an input to a PID loop controlling the torque reference of your winder or unwinder.
Now, to use torque control you can't use hobby-servos which all run in position control mode via PWM. You can use "proper" servomotors, which are expensive, or you can use DC motors with a PWM driven motor driver board. Use the current feedback as the setpoint variable in your PID, and you're golden.
And never drive two steppers on the same winder, that's rule one.
News - Ladder Logic
about 2 years ago
Also, as points of interest, I believe that is a Melsec in Paul’s title picture. And please notice the “tape” jack on the programming
terminal- that’s right, we used to store programs on cassettes.
If you guys want some pictures of ancient programming terminals and PLC’s, wait til I get to the office tomorrow! I’ve got
And Koyo made (makes) that same PLC for GE/Fanuc, Siemens, Texas Instruments, and PLC/Automation Direct. A 100
Word demo IDE is downloadable free from automationdirect.com.
The text language Paul is using is implemented by other older PLC manufacturers, particularly Mitsubishi’s early Melsec
series. But other manufacturers ASCII interface looked like this “xio bst xic nxb xic bnd xic ote.” Extra credit to Paul or anyone else that can translate that to a ladder diagram…
“Hammer Smashed Face”- Excellent choice, Chris! I generally prefer to program HID’s while listening to Grave’s “You Will Never See”, but to each his own…
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