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2/22/2013 3:45 AM | |
Joined: 5/26/2011 Last visit: 11/14/2024 Posts: 456 Rating:
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Hello Experts! Especially to you two Cicero and hdhosseini! What if the valve action is not (although the command is) binary, but modulating ? In that, energizing the digital output, depending on your energization/pulse duration, the valve/motor commands increase (or decrease if on the decrease output) position/speed? That is, for instance, an energization/pulse length of 1s would give a 2% increase (or decrease if on the decrease output) whereas an energization/pulse length of 2s would give, say, 3% or 4% increase/decrease? How could we control this using PID? Or is it even possible? Is PULSEGEN really applicable in this case? In all this questions, the answer, it seems to me, is negative. What we have created as a solution for automatic control of the said binary-output-but-modulating-actuator is a pulser program in that, depending on the error (SP-PV) it would give corresponding pulse in either increment or decrement, with a constant pulse duration (on/off). The problem with this is that it only resembles the Proportional action of the PID controller (not even entirely, because we don't have a variable gain for tuning), that which is totally insufficient to control a dynamic variable with multiple distrubances. And because of this, we are just operating manually, for using this control just makes the process value oscillate. In short, it doesn't work. What I think as a possible solution is to resemble, at least the Proportional and Integral tuning of the PID controller by making the pulse duration (as gain) and the pulse interval (as integral) variable. But this, still, would be insufficient, for even it seems to resemble the tuning part, it would not resemble the control action (esp. the integral), for, even the pulse is not, say, 1sec on/off, the command/response would still be constant (say .5 sec on/2sec off, constantly)! Could you, knowledgeable guys, please give me any alternative solution/s? Thanks for any response! |
Last edited by: O_Moderator at: 2/22/2013 12:55 PMnew subject after splitting from /tf/WW/en/Posts/85734#top Last edited by: nicer at: 2/22/2013 4:07 AMLast edited by: nicer at: 2/22/2013 4:05 AMLast edited by: nicer at: 2/22/2013 4:03 AM |
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2/22/2013 12:57 PM | |
Joined: 4/24/2009 Last visit: 8/20/2024 Posts: 2682 Rating:
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Thread closed, because question is already published in the following thread PULSEGEN For a Binary Output-But-Modulating-Actuator Best regards O_Moderator |
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