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3D tables

Created by: quique at: 2/22/2006 2:44 PM (8 Replies)

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2/22/2006 2:44 PM	Rate (0)
quique Posts: 5 Rating: (0)	Hello, I would like to create 3D tables in my S7-400. I have several tables which have 2 inputs and 1 output. I did not find any structure alike in the libs. Only a 2D table (Modular PID library) called NONLIN where you can have a single input/output table. For example Temperature and Pressure as Inputs and then Density as Output. Temp 10.2 15.3 20.1 34.5 Pressure 2.0 23.3 34.5 67.5 89.8 3.4 13.2 23.2 42.1 56.7 4.6 10.8 23.2 67.9 89.9 So the result of having T=15.3 and P=3.4 is 23.2 and evidently it must interpolate between points as NONLIN funciton does for the case of a 2D table. Do you know anything I could eventually use? Thanks in advance, Quique
quique Posts: 5 Rating: (0)
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2/22/2006 6:06 PM	Rate (0)
Denilson Pegaia Platinum Member Joined: 9/23/2005 Last visit: 9/22/2023 Posts: 4235 Rating: (1366)	Hi, it's possible crate a 3D table in STEP 7. See the follow sample: DATA_BLOCK DB 1 TITLE = VERSION : 0.1 STRUCT a : ARRAY [1 .. 3, 1 .. 3, 1 .. 3 ] OF REAL ; END_STRUCT ; BEGIN a[1, 1, 1] := 0.000000e+000; a[1, 1, 2] := 0.000000e+000; a[1, 1, 3] := 0.000000e+000; a[1, 2, 1] := 0.000000e+000; a[1, 2, 2] := 0.000000e+000; a[1, 2, 3] := 0.000000e+000; a[1, 3, 1] := 0.000000e+000; a[1, 3, 2] := 0.000000e+000; a[1, 3, 3] := 0.000000e+000; a[2, 1, 1] := 0.000000e+000; a[2, 1, 2] := 0.000000e+000; a[2, 1, 3] := 0.000000e+000; a[2, 2, 1] := 0.000000e+000; a[2, 2, 2] := 0.000000e+000; a[2, 2, 3] := 0.000000e+000; a[2, 3, 1] := 0.000000e+000; a[2, 3, 2] := 0.000000e+000; a[2, 3, 3] := 0.000000e+000; a[3, 1, 1] := 0.000000e+000; a[3, 1, 2] := 0.000000e+000; a[3, 1, 3] := 0.000000e+000; a[3, 2, 1] := 0.000000e+000; a[3, 2, 2] := 0.000000e+000; a[3, 2, 3] := 0.000000e+000; a[3, 3, 1] := 0.000000e+000; a[3, 3, 2] := 0.000000e+000; a[3, 3, 3] := 0.000000e+000; END_DATA_BLOCK To interpolate values in a 3D table, how ever it's necessary create a proper algoritimus. I think that is possible find a solution with cascade interpolations, I don't remenber the algorithimus.
	Last edited by: Pegaia at: 2/22/2006 6:08 PM Denilson Pegaia Siemens Industry Sector Technical Support
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2/22/2006 11:44 PM	Rate (0)
quique Posts: 5 Rating: (0)	Thank you for your answer. Nevertheless I guess this is quite differente from what I want to obtain. In your proposition the access of the table is made by index and not by value. In my case you would find the next function Output=f(input1, input2) where inputs are float values. Thanks again, Qq
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2/23/2006 8:59 PM	Rate (0)
Denilson Pegaia Platinum Member Joined: 9/23/2005 Last visit: 9/22/2023 Posts: 4235 Rating: (1366)	Hi, you can mount 3 tables: A X Table, unidimentional, for the x values A Y Table, unidimentional, for the y values A F(x,y) Table, bidimentitional, for the output values for x,y Placex andy valuesin the Tables X and Y in the same order that you place F(X,Y). Then, you muss mount a logic to searchthe value xin the Table X. In the same way, use a equivalent logic to find y in the Table Y. Use the indices of x and y in the Table F(x,y).
	Denilson Pegaia Siemens Industry Sector Technical Support
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5/3/2006 9:17 AM

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MartAnd

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Hello quique!
I encountered the same problem once and I solved it by simply creating my own FB for the given grid of numbers (x,y)e.g. temperature and pressure. Sincemy gridhad good resolutionI used linear interpolationinside it with good result.

Attached is a FB that with small adjustments could be used for your purpose. Make sure you understand thestructure beforeyou change the size of the grid!

Regards Mårten

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LIN_INTER.zip (297 Downloads)

5/10/2006 3:13 PM	Rate (0)
quique Posts: 5 Rating: (0)	Thank you very much. I'll try to give a look to it, even if it's written in IL!! [:o] I do not remember last time I've made something in IL. [:blush:]. Thanks again, Quique
quique Posts: 5 Rating: (0)
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5/18/2006 4:54 PM	Rate (0)
MartAnd Posts: 31 Rating: (2)	Hi again quique! My intention wasn't to make things difficult so I have developed the same Function Block in SCL instead. Now it should be easy for you to add your own values e.g. those in your first post and get a resonable answer out of them. Irecommend you torun the FBwith a simulator before you go sharp! Regards Mårten Attachment LIN_INTER.zip (289 Downloads)
MartAnd Posts: 31 Rating: (2)
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5/22/2006 10:04 PM	Rate (0)
Denilson Pegaia Platinum Member Joined: 9/23/2005 Last visit: 9/22/2023 Posts: 4235 Rating: (1366)	Hi, I wrote a documentation about the thema. Attachment Interpolation.zip (306 Downloads)
	Denilson Pegaia Siemens Industry Sector Technical Support
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5/22/2006 10:10 PM	Rate (0)
Denilson Pegaia Platinum Member Joined: 9/23/2005 Last visit: 9/22/2023 Posts: 4235 Rating: (1366)	Hi, I write a sample too Attachment Interpol.zip (310 Downloads)
	Denilson Pegaia Siemens Industry Sector Technical Support
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Created by: quique at: 2/22/2006 2:44 PM (8 Replies)

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Last edited by: Pegaia at: 2/22/2006 6:08 PM

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