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Any Pointer, Read string from DB, SCL

Created by: AWestEng at: 9/4/2007 10:19 AM (30 Replies)

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9/5/2007 9:16 PM	Rate (2)
Dec Gold Member Joined: 5/19/2006 Last visit: 8/21/2025 Posts: 550 Rating: (107)	Here is my try; When call FC1 (COM_STRING) you do: CALL "COM_STRING" Input_Data :="STR_DB".In_String Output_Data:="STR_DB".Out_String Data_Leght :=MW100 When you call AG_SEND SEND:=P#DB1.dbx258.0 byte 24 Dec Attachment COM_STRING.zip (697 Downloads)

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9/6/2007 7:37 AM	Rate (0)
Aret Posts: 2348 Rating: (265)	Dec, nice code :^) AWestEng, notice, that in my example IN variable is STRING. In Dec's example it's ANY. But we both supply STRING parameter.Soyoumustdothesame-asinputuseSTRINGparameterbySYMBOLICname.
Aret Posts: 2348 Rating: (265)
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9/6/2007 11:43 AM	Rate (0)
AWestEng Posts: 13 Rating: (0)	hehe,, shit that's alot of nice code.. I have to try to understand all the code now.. Oki so the input is not a pointer is the string value by using the symbol name. But when using the symbolname is the type inANY? Just trying to understand how this works,, This is what's confusing me. When reading a stringfrom the DB with symbolic name is that in ANY orin string? VAR_INPUT Input_Data :ANY; END_VAR
AWestEng Posts: 13 Rating: (0)
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9/6/2007 12:41 PM	Rate (1)
Aret Posts: 2348 Rating: (265)	Ok, sutiation - you have FC with input parameter ANY. That's called formal parameter of function. When you supply P#.... to input "P#..." is called actual parameter. General rule says, that types of formal and actual must match. Iftheydonottheymustbeconvertable.Instep7usuallytypes must exactly match (WORD and INT are convertable, but you can't supply formal INT with actual WORD). Then -youcanusesymbolicnameinsteadactualparameter. Thencompilertakesthisparameter'stypefromsymbol table. There is only 1 exception - ANY :^) You can supply formal ANYwithactualanytypeparameter(INT,WORD,REAL,STRING....) - even though it's not ANY. Whathappendsifyoudothat(forex.MW20asactualparam)? Compiler itself creates P#M20.0 WORD 1 andsuppliesthis asactualparametertofunction (instead of MW20).SoStep7tricksyoualittle-yousee MW20, but in fact that's P#M20.0 WORD 1. Back to our examples. Actual parameter is DB1.Input_string : STRING. Formal parameter isInput_Data: ANY (in Dec's example). When you make ":=" DB1.Input_string is replaced by P#DB1.DBX....STRING1. PS. I can advise to visit Siemens courses of advanced Step7-programming, called PRO2. There are many things to mention about indirect addressing and ANY variables - it takes about 2 days to tell everything. Or read some books, as standart help is not very usefull here.
Aret Posts: 2348 Rating: (265)	Last edited by: Aret at: 06.09.2007 12:46
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9/6/2007 3:44 PM	Rate (0)
AWestEng Posts: 13 Rating: (0)	Oki.. that explains alot. Can I thenchange the input ANYto STRINGif i use the symbolic name? And if that's possible, isit better using STRING as a input regarding converting the output to ANY. I mean is it easyer to input ANY if you want to output ANY or is it better so insert STRING fix the string and then convert it to ANY? Have I understand this correct: Input_Data_Temp_Struct.S7 = B#16#10: That the code only can be run on a S7 system Input_Data_Temp_Struct.Data_Type = B#16#2: That theinput type must be BYTE Input_Data_Temp_Struct.Data_Cnt > 0: The size of the input data must be "someting" Input_Data_Temp_Struct.DB_No <> 0: That DB number cannont be 0 (Should I not test the DB Nr before the size?) These twoI dont' understand //Check for Area DB (0x84) SHR(IN:=Input_Data_Temp_Struct.Area_And_Offset, N:=24) = B#16#84) //Check for bit index = 0 Input_Data_Temp_Struct.Area_And_Offset AND DW#16#7) = B#16#0 And one other thing: I can't see that the COM STRING is written to the Output "Output_Data" only to the DB, or is i just me that is missing something in the code?
AWestEng Posts: 13 Rating: (0)	Last edited by: AWestEng at: 06.09.2007 17:20 Last edited by: AWestEng at: 06.09.2007 16:22
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9/9/2007 3:31 PM	Rate (0)
Aret Posts: 2348 Rating: (265)	>>Can I then change the input ANY to STRING if i use the symbolic name? Yes. >>I mean is it easyer to input ANY if you want to output ANY or is it better so insert STRING fix the >>string and then convert it to ANY? Depends on what is easier for you^)Think2ndvariantisabiteasier. >>Input_Data_Temp_Struct.S7 = B#16#10: That the code only can be run on a S7 system >>Input_Data_Temp_Struct.Data_Type = B#16#2: That theinput type must be BYTE yes >>Input_Data_Temp_Struct.Data_Cnt > 0: The size of the input data must be "someting" not really size, but quantity >>Input_Data_Temp_Struct.DB_No <> 0: That DB number cannont be 0 It can if you don't use DB/DI for ex. P#M0.0 BYTE 10 would contain 0 in this field >>These two I dont' understand >>//Check for Area DB (0x84) >>SHR(IN:=Input_Data_Temp_Struct.Area_And_Offset, N:=24) = B#16#84) Input_Data_Temp_Struct is so-called area-crossing pointer (32-bit). It containssomething like P#M0.0orP#DBX32.0.Thiscodechecks if DB is used or not. >>//Check for bit index = 0 >>Input_Data_Temp_Struct.Area_And_Offset AND DW#16#7) = B#16#0 Well, you cant make pointer like P#M0.1 BYTE 3. Because bit number <>0. So you must check if bit number =0. Try Area-crossing indirect addressing in standart Step7 help for details - there is format of 32-bit pointer. >>And one other thing: >>I can't see that the COM STRING is written to the Output "Output_Data" only to the DB, or is i >>just me that is missing something in the code? FOR Index := 0 TO Input_Data_Str_Act_Len -1 DO WORD_TO_BLOCK_DB (Output_DB_No).DB[Output_Data_Offset + 14 + Index] := WORD_TO_BLOCK_DB(Input_DB_No).DB[Input_Data_Offset + Index + 2]; END_FOR; Ps. Thanks for starts^)
Aret Posts: 2348 Rating: (265)	Last edited by: Aret at: 09.09.2007 15:32
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9/9/2007 3:32 PM	Rate (0)
Aret Posts: 2348 Rating: (265)	Dec, if you add W#16#85 codeit will workwithDIalso.
Aret Posts: 2348 Rating: (265)
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9/10/2007 2:45 PM	Rate (0)
AWestEng Posts: 13 Rating: (0)	But what i can see in that code you pasted is ony that you wirite it to the DB out string not to the ANY variable "Output_Data"
AWestEng Posts: 13 Rating: (0)	Last edited by: AWestEng at: 10.09.2007 14:58
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9/10/2007 9:09 PM	Rate (0)
Dec Gold Member Joined: 5/19/2006 Last visit: 8/21/2025 Posts: 550 Rating: (107)	AWestEng And one other thing: I can't see that the COM STRING is written to the Output "Output_Data" only to the DB, or is i just me that is missing something in the code? There is nothing you can write direct to the FCparameter output "Output_Data" 12 bytes ANY. That is just a reference (ANY Type) to the location where Output_Data exist (DB1.Out_String). You can define "Output_Data" as FC input parameter as well if that makes you understand better. Dec

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9/11/2007 9:37 AM	Rate (0)
AWestEng Posts: 13 Rating: (0)	ok so if I understand this correct you don't actually write anything on the output vaibale you write to the output string in the DB and that one you put on the output of the FC and then youactually readthe output and put that one into the ANY variable Output_Data. So I hope understand what you are doing now.. Thx alot..
AWestEng Posts: 13 Rating: (0)
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