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SPLIT RANGE CONTROL!

Created by: Gunners at: 4/17/2009 10:44 AM (12 Replies)

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4/17/2009 10:44 AM	Rate (0)
Gunners Posts: 130 Rating: (18)	HI ALL, I have to write the logic for Split Range Control. i.e; I am splitting the PID controllers output to 2 control valves A & B , in such a way that when one is opening 0-50% the other should open from 50-100%. can anyone tell me whether we have any block in SIMATIC PCS7 Library to do this? if not how can i do this? i am attaching the loop as .pdf file thanks Attachment Document3.pdf (436 Downloads)
Gunners Posts: 130 Rating: (18)
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4/17/2009 11:04 AM	Rate (0)
Sydney Gold Member Joined: 1/4/2008 Last visit: 3/8/2023 Posts: 703 Rating: (95)	Hello, maybe I haven't understoodthe problem, but looks so simple:percentage output of the PID splitfor requested position oftwo valves using linear conversion. For the first one from 0-50 to 0-100, for the second one from 50-100 to 0-100. Regards Sydney

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4/17/2009 11:26 AM	Rate (0)
Gunners Posts: 130 Rating: (18)	Hi, I dont think you understood the question. please read carefully. – Point at which we need to split the PID output signal. i.e. PID output is 0-100%. We need to split between two valves as 0-X% and X-100%.Here X is called as split point. You spoke about linear conversion? i am talking about using a Function block to do this in FBD programming. is there any calculation block in the library to do this function? how will you do this?
Gunners Posts: 130 Rating: (18)
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4/17/2009 12:01 PM	Rate (0)
Mario Braganca Posts: 124 Rating: (17)	Hello all Please see this (item 2.1.18) PCS 7 V7.0 Library This block exists also in V6.0 and 6.1. Regards Mario Braganca
Mario Braganca Posts: 124 Rating: (17)
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4/17/2009 12:07 PM	Rate (0)
Sydney Gold Member Joined: 1/4/2008 Last visit: 3/8/2023 Posts: 703 Rating: (95)	I understood that the output from PID should be used for two valves in this way: In the range 0-50 the first valve is operating (with its range 0-100% open) and the second is closed, in the range 50-100 the first is opened and the second is operating (with its range 0-100% open). If it shouldwork by another way, please describe it more precisely. Regards Sydney oops, I forget that it's PCS7 conference , then theSPLITR_P block mentioned by Mario Bragancacan help... but it makes the function I described so will it help if I wrong understood the problem?
	Last edited by: Sydney at: 4/17/2009 12:18 PM addition
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4/17/2009 1:08 PM	Rate (0)
CBo Gold Member Joined: 4/5/2006 Last visit: 3/18/2023 Posts: 917 Rating: (63)	hi Pratapks, not sure to understood if you are talking about split-range function or something different but similar. Lets me do an example: - PID output range is between 0-100% - 2 analog valve 0-100% range (0=completely closed, 100=comletelly open) - 40% split-range point (just for example) PID output = 0% : 1st valve =100% , 2nd valve 0%; PID output = 40% : 1st valve = 0% , 2nd valve 0%; PID output =100% : 1st valve = 0% , 2nd valve 100%; This is split-range function Sydney&Mario Bragança said (standard split-range function) already present in PCS7 library where it's possible change the split-range points and invert output range to make workiing the valvs in opposite way. If you need a different function can you explain with more detail or numeric example? Regards

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12/21/2014 7:22 AM	Rate (0)
Chandra Tiwari Posts: 247 Rating: (2)	Dear Experts, Any one can suggest how to do spli range control for 2 control valve using 1 pid in manner of 0-90% and 0-10% I am using PCS7 V8.0 with IL for PLC S7-300.
Chandra Tiwari Posts: 247 Rating: (2)
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12/22/2014 3:45 PM	Rate (0)
RugbyGuy Silver Expert Joined: 1/15/2009 Last visit: 3/15/2022 Posts: 316 Rating: (40)	@RaviS Try usint the S7SplitRange block. To understand more about the block, hit F1 and go to section 10 Diagram of a Split Range Control Process. THis will show you the calculation and diagrams (as you can use up to 4 split ranges per controller output). Good luck
	The best location for all PCS 7 content (manuals, guides, application notes, FAQs, and videos). https://support.industry.siemens.com/cs/ww/en/view/63481413
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This contribution was helpful to 1 thankful Users Chandra Tiwari

1/4/2015 3:13 PM	Rate (0)
Chandra Tiwari Posts: 247 Rating: (2)	Hi RungbyGuy, I tested but seems not as per client's expactationsthis split range is limiting the valve opening as per limit SP, and looks like say 95% its splitting it in 90% and 5% which is not suitable for my application. My case is like this: I have 2 valves, 1st= 0-90% and is bigger in size, other 2nd= 0-10% is smaller in size. For eg. 1) PID output is 9 theninitiallyvalve (2nd valve) should open and bigger (1st) valve will be closed only 2) PID o/p= 11 theninitiallysmall valve (2nd valve) should open say 100% of 10% contribution and then bigger (1st) valve will open for the remaining contribution 3) PID o/p=25 then initially small (2nd) valve should open and then bigger valve will open. and so on.... now for eg. the PID o/p= (less than the previous o/p) then also initially small (2nd) valve should close and then bigger valve will close. Its like fine and course type of control for reactor temperature management. any other blocks I have or have to do in manually.
Chandra Tiwari Posts: 247 Rating: (2)
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1/6/2015 9:56 AM	Rate (0)
Jules Stohr - Sto... Bronze Member Joined: 12/22/2014 Last visit: 10/7/2021 Posts: 173 Rating: (23)	Hello RaviS I have created a linear conversion function for a customer. This function could be inserted twice for each valve. Please see the attached screenshot of the faceplate of the function for two valves (example). It is possible to enter the parameters on screen but also fixed in the CFC chart. The small valve opens between an PID output of 0-10% and the large valve opens between an PID output of 10-100%. Sorry about the dutch text. Is this something you are searching for? Attachment PID Split.jpg (456 Downloads)
	Greetings Jules Stohr Stohr Industrial Automation BV Netherlands
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