3/14/2016 12:29 PM | |
Posts: 567 Rating: (106) |
Hi Berg, maybe this application example gives some Information. https://support.industry.siemens.com/cs/ww/en/view/53843373 |
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3/14/2016 2:05 PM | |
Joined: 1/17/2006 Last visit: 4/8/2024 Posts: 552 Rating: (29) |
Hi Ralfinio ! Thanks for the reply. It's a very interesting link... regards.
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3/15/2016 7:16 AM | |
Joined: 3/14/2008 Last visit: 4/26/2024 Posts: 2066 Rating: (927) |
Goodmorning! Attached is a document I wrote, because I had to implement a split range control once. It is written according to PCS7 6.1. I did a few tests and the outcome is listed in the document. It's a good document I wrote, the understanding of split range is a lot clearer now. AttachmentSplit range control.pdf (181 Downloads) |
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3/17/2016 10:25 PM | |
Joined: 3/14/2008 Last visit: 4/26/2024 Posts: 2066 Rating: (927) |
Hi Berg, Well, I'm not exactly an expert on MPC controllers, but I can tell you what I know... The MPC controller is used to determine how a process will function. It predicts this process by using multiple inputs. In the Chemical Industry example, the desired pH value is regulated by using a neutralizing agent. Instead of using a normal PID controller, a MPC controller is used. This is due the fact that the concentration of the pH is non linear. Also, there are other "disturbances" in the process, like dead times of the pH measurement, mixing time and the reaction of the neutralizing agent on the pH value. You cannot accomplish a good process control with a standard PID controller, because the PID controller's MV output is based on a error signal between PV and SP in the past. That is why a MPC is used, because the MV output is based on control deviations in the future. In a MPC controller the inputs can have influence on each other (see attachment). In this example: pH input, flow input, neutralizer agent input and pH output. For the example: When you change the SP, the controller will slowly work on getting to the SP. The controller recognizes changes in the disturbance value and changes the MV value before the process reacts to the change of the disturbance. I hope this info is useful to you! |
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