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Determining the instance DB number of an FB using SCL

Created by: Nanook at: 1/2/2009 11:14 PM (8 Replies)

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1/2/2009 11:14 PM	Rate (1)
Nanook Member Joined: 7/23/2008 Last visit: 7/22/2021 Posts: 5 Rating: (1)	I'm looking for a method of doing in SCL what I've seen done in STL. There are many times when it would be beneficial to determine what instance data block is being utilized by a given function block. The STL block I've seen uses the CFC block interconnection in order to get the instance DB number. I cannot find a similar method using SCL. I realize I could assign my own DB number, but that's not really an option and defeats some of the power of using PCS7 to assign DB's as necessary. Ideally I need to simply be able to "read" what DB number a given function block is currently utilizing.

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1/6/2009 9:47 AM	Rate (5)
GrzegorzG Posts: 63 Rating: (19)	You can determine number of opened instance DB by assigning adress of any IN, OUT or STATIC variable to ANY pointer inside FB and then get the number of opened instance from it's structure using AT statement. For example VAR BitVar: bool; // static variable of FB END_VAR VAR_TEMP AnyPtr: ANY; AnyStruct AT AnyPtr: STRUCT S7_ID: BYTE; Mem_ID: BYTE; NumberOfElements: INT; DB_Number: WORD; BitPointer: DWORD; END_STRUCT; END_VAR BEGIN AnyPtr:= BitVar; // SCL assigns full ANY pointer to AnyPtr // after this statement AnyStruct.DB_Number cointains instance DB number that can be used in your code
GrzegorzG Posts: 63 Rating: (19)
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This contribution was helpful to 6 thankful Users Nanook crazyCow karriandr Sachinpatke LuWiack Jacek T

1/6/2009 2:55 PM	Rate (0)
Denilson Pegaia Platinum Member Joined: 9/23/2005 Last visit: 3/22/2023 Posts: 4180 Rating: (1332)	Hi, in STEP 7 there is two sistem variables that return the actual opened DB and DI(DBNO and DINO). I think that you can use it not only in STL but also in SCL.
	Last edited by: Pegaia at: 1/6/2009 2:55 PM Denilson Pegaia Siemens Industry Sector Technical Support
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This contribution was helpful to 3 thankful Users norenendur rapido4 LuWiack

1/6/2009 3:23 PM	Rate (0)
Nanook Member Joined: 7/23/2008 Last visit: 7/22/2021 Posts: 5 Rating: (1)	Thank you for the replies. Not long after I wrote the post I found the answer and solved it very much as Gregor described. I'll have to try using DBNO.

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7/17/2014 12:10 AM	Rate (0)
WizZed Posts: 1 Rating: (0)	A link to your solution would be very helpful
WizZed Posts: 1 Rating: (0)
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7/18/2014 10:53 AM	Rate (0)
Aret Posts: 2348 Rating: (259)	Use GrzegorzG's solution. SCL has no DBNO command as i know.
Aret Posts: 2348 Rating: (259)
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7/18/2014 4:10 PM	Rate (0)
smiffy Platinum Expert Joined: 1/17/2007 Last visit: 3/17/2023 Posts: 1523 Rating: (518)	Aret Use GrzegorzG's solution. SCL has no DBNO command as i know. You're correct, it does not.
	Programming today is the race between software engineers building bigger and better idiot proof programs, and the universe producing bigger and better idiots. So far, the universe is winning...
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7/23/2015 4:58 PM	Rate (0)
AutoGen_889998 Posts: 1 Rating: (0)	Dear Colleagues, Here is the solution: Create a function in STL and use the following code: L DINO T RET_VAL Then call this function in your function block.
AutoGen_889998 Posts: 1 Rating: (0)
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8/24/2015 2:40 PM	Rate (0)
Remark Bronze Member Joined: 9/1/2006 Last visit: 2/25/2023 Posts: 192 Rating: (12)	AutoGen_889998 Dear Colleagues, Here is the solution: Create a function in STL and use the following code: L DINO T RET_VAL Then call this function in your function block. I don't think this will work for all situations (it might work for a 300/400 CPU) TIA won't let you execute a L DINO (the compiler will give an error for an 1500 cpu) TIA tries to protect you against a programming error, you didn't open a DI so why ask for it's number.... A warning would be nice for some less experienced programmers but to give an ERROR... mmmh In a 1500 CPU this probably makes sense since calling an FC will probably changes the DI/DB registers to protect against unwanted data access. Until Siemens adds an SCL GET_DINO instructions i'll use Gregs method. regards, Remark
	Last edited by: Remark at: 8/24/2015 2:43:05 PM
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