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SCL: call function indirect ( FC[#no], similar to UC in STL )

Created by: Jens_app at: 5/8/2014 9:47 AM (8 Replies)

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5/8/2014 9:47 AM	Rate (1)
Jens_app Gold Member Joined: 1/5/2011 Last visit: 10/27/2023 Posts: 814 Rating: (120)	Dear all, I'm trying to call a function indirectly, so I can pick my own sequence on how my functions are executed and which functions are executed. Something similar to "UC FC[MW10]", but then in SCL. Can anyone help me out? Thanks in advance. Kind regards, Jens
	Keep it simple and on-topic. A simple straight-to-the-point answer is often of more quality than a complicated one.
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5/8/2014 12:11 PM	Rate (0)
Jens_app Gold Member Joined: 1/5/2011 Last visit: 10/27/2023 Posts: 814 Rating: (120)	I now have a workaround with case selects, but I don'tthink this isthe best solution. I think it's more "clean" if I can achieve the same as UC inSTL (but then in SCL). Ok, so this is what I'm doing now, underneath the code snippet: ____________________________________________ FUNCTION_BLOCK "FB_UnconditionalCallsTest" VAR_INPUT "SelectFC" : Int; END_VAR VAR_OUTPUT "Result" : Int; END_VAR VAR_IN_OUT "Index" : Int := 0; "CalculatedValue" : Int; END_VAR BEGIN #SelectFC := "DB_SequenceSelect".SequenceSelect[#Index]; CASE #SelectFC OF 1: "FC_Multiply"(#CalculatedValue); 2: "FC_Substract"(#CalculatedValue); ELSE RETURN; END_CASE; #Index := #Index + 1; IF #Index = 11 THEN #Index := 0; END_IF; END_FUNCTION_BLOCK __________________________________ DATA_BLOCK "DB_SequenceSelect" STRUCT "SequenceSelect" : array[0..10] of Int; END_STRUCT; __________________________________ DB_SequenceSelect containing the function that needs to be executed according to the index. Now this works great, but it's too much code for what it's doing. I'd rather do something like: FC[#index]. KR, Jens
	Last edited by: Jens_app at: 5/8/2014 12:31 PM Update, added code snippet and explanation Keep it simple and on-topic. A simple straight-to-the-point answer is often of more quality than a complicated one.
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5/8/2014 12:52 PM	Rate (0)
William_B Posts: 5225 Rating: (1182)	wow.. that is an interesting idea! I agree though that much coding is required to achieve your result. (Did I miss the for-loop instruction in the snippet.) Doing it the way you hoped to do it, does limit portability into other (foreign) projects. If the coding is not too much you can have all coding inside one FC. Every block of code can start with a label and end with a return instruction. A "case" (SCL) or "switch" (LAD) can be used to jump to the relevant code segment (label). As parameters to the FC you also give a "segment" (label) number. ..it is not as elligant as what you are looking for, but it will work. w
William_B Posts: 5225 Rating: (1182)
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5/8/2014 1:35 PM	Rate (0)
Jens_app Gold Member Joined: 1/5/2011 Last visit: 10/27/2023 Posts: 814 Rating: (120)	William B. wow.. that is an interesting idea! I agree though that much coding is required to achieve your result. (Did I miss the for-loop instruction in the snippet.) Doing it the way you hoped to do it, does limit portability into other (foreign) projects. If the coding is not too much you can have all coding inside one FC. Every block of code can start with a label and end with a return instruction. A "case" (SCL) or "switch" (LAD) can be used to jump to the relevant code segment (label). As parameters to the FC you also give a "segment" (label) number. ..it is not as elligant as what you are looking for, but it will work. w Hi William, you did not miss the for loop, I didn't include it. Since everytime the FB executes again it would loop index from 0 to 10, but I want the last index value to be stored when the function exits, so when the function starts again it doesn't restart from index 0 but rather resumes from where it ended. What you are saying is right, I would have to re-make this function for every other project, but I'd rather re-use it, that's why it would be so nice to use UC (like in stl). For the same reason I do not fully agree on using jump labels in one function, since this function would again be "bound" to this project and I would have to re-make it for another project. And I find working with cases and seperate functions still a bit cleaner then the suggestion of using jumps and labels. Still I do like you putting out suggestions and in some cases working with jumps is the answer, it just isn't the answer in my case. Thanks anywayforyour concern, it's always nice to have input from programmers with knowledge! Kind regards, Jens
	Keep it simple and on-topic. A simple straight-to-the-point answer is often of more quality than a complicated one.
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5/8/2014 3:12 PM	Rate (0)
William_B Posts: 5225 Rating: (1182)	No worries my friend. It is healthy to voice your ideas to find better solutions. There is no way for us to know the detail to each other's coding environment. ..so we have to guess a little -- and sometimes it works; sometimes for someone else. I loved STL to pieces when I worked on S7-300 projects. For small footprint, fast running code there were no option, back then. Generating code through EXCEL spreadsheets via STL is a winner. It is nice that you could mix the STL and LAD. Service personal from clients however do not like STL; regardless of how well the documentation is. Sadly the S7-1200 do no allow STL and no mixing SCL and LAD within the same FB/FC. ..but we just have to adapt to what we get to work with.
William_B Posts: 5225 Rating: (1182)
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This contribution was helpful to 1 thankful Users Jens_app

5/8/2014 3:20 PM	Rate (0)
Jens_app Gold Member Joined: 1/5/2011 Last visit: 10/27/2023 Posts: 814 Rating: (120)	Good thing adapting is one of my specialties I will for now settle with a workaround. If any other suggestions come to mind, you'd be kind to let me know. Thanks William. KR, Jens.
	Keep it simple and on-topic. A simple straight-to-the-point answer is often of more quality than a complicated one.
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5/8/2014 4:47 PM	Rate (0)
William_B Posts: 5225 Rating: (1182)	One thought did come up.. just give some thought to it.. (..maybe I am preaching to the choir?) Be careful for trying to find THE best solution. Too many of us regularly get caught in that trap. (I include myself.) YES it is good to ask the question, but it is MORE important to solve the problem. It is very positive if your solution can be followed easily by another person. (There are actually ways of coding that does self documenting.) Bonus points if that solution can be transfered/adapted to other projects. With today's technology we can be less worried about getting the optimum solution. It is however a high priority to get the solution in the least time. The client pays for the solution.. as in result.. not the path taken. Time is better spent in finding techniques and tools to develop coding more automaticaly. Spreadsheets can for example be such a tool (I love "concatenate" / "&" function). that is my 2c w
William_B Posts: 5225 Rating: (1182)
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5/8/2014 5:09 PM	Rate (0)
Jens_app Gold Member Joined: 1/5/2011 Last visit: 10/27/2023 Posts: 814 Rating: (120)	William B. One thought did come up.. just give some thought to it.. (..maybe I am preaching to the choir?) Yes William, you are peaching to the choir , I agree with what you are saying TIME IS MONEY!That's why I'm investing mytime in constructing the best re-usable function. Causethetime that's now being spent will surely be regained in the long run. KR, Jens
	Keep it simple and on-topic. A simple straight-to-the-point answer is often of more quality than a complicated one.
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11/30/2023 12:41 PM	Rate (0)
Jen_Moderator Moderator Joined: 6/19/2017 Last visit: 12/1/2023 Posts: 7589 Rating: (154)	New question published by AutoGen_2161647 is split to a separate thread with the subject call functions by number. Best regards Jen_Moderator
	My Forum is the place to personalize your profile, track your topics, and maintain content that interests you. Best regards Jen_Moderator
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