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Creating FB

Created by: sakal123 at: 11/23/2011 8:59 AM (11 Replies)

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11/23/2011 8:59 AM	Rate (0)
sakal123 Posts: 29 Rating: (0)	Hello! I have a working part of code which I would like to put in its own function due to often and easier use. I'm putting all of local/inside variables (that need to be written in DB) to STAT field and of course they show up in DB. Here is the part of code I have problems with (LAD): MD312 -> ROUND -> MD316; MW318 -> I_BCD -> MW320 I need 2 parts of that "MD316". I don't know how to read that "MW318" because I can't create it in STAT (next available address after "MD316" is "MD320") - in normal programing I would simply write "DB2.DBW318" but if I'm making FB for multiple use I can't do that.
sakal123 Posts: 29 Rating: (0)
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11/23/2011 10:10 AM	Rate (0)
miami Platinum Member Joined: 8/31/2005 Last visit: 9/12/2025 Posts: 2198 Rating: (331)	Use theIN and OUT part of the FB to define inputs and outputs. When you call the FB you can define which values it should use for eachinstance and where to put the results. Habe a look on the attachment for a example. Attachment Forum.pdf (359 Downloads)

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11/23/2011 11:14 AM	Rate (0)
sakal123 Posts: 29 Rating: (0)	I get that, it is fine, but... I use this code (that was only a part of it) for mul and add operations with S5TIME. So I use input_time and output_time for IN and OUT parameters. I would like to make it as user friendly as it can be, so that the user of this FB would specify only IN and OUT parameters and not the addresses of those middle parameters (312-320) which are needed to be read only for the program to work (not needed for the user) - could it be done in the background?
sakal123 Posts: 29 Rating: (0)
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11/23/2011 11:33 AM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 8/31/2025 Posts: 6874 Rating: (1368)	sakal123 I would like to make it as user friendly as it can be, so that the user of this FB would specify only IN and OUT parameters and not the addresses of those middle parameters (312-320) which are needed to be read only for the program to work (not needed for the user) - could it be done in the background? Dear sakal123 , The absolute addresses in instance DB generated automatically as FB called. I hope this helps. Best regards, Hamid Hosseini
	Demo Channel on Youtube
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11/23/2011 12:57 PM	Rate (0)
miami Platinum Member Joined: 8/31/2005 Last visit: 9/12/2025 Posts: 2198 Rating: (331)	If you only use the Marker memory to store some internal values, you can easyly switch to STAT variables. And if you get the values to convert from somwere elseyou can use this as input for your FB, e.g.EW78 or DB5.DBD4

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11/23/2011 2:22 PM	Rate (0)
sakal123 Posts: 29 Rating: (0)	Hum sorry if I don't understand quite right. Those are internal values and they obviously shouldn't be Markers due to use perhaps even in different programs. That is why I put those as STATs in the first place. I just have a problem reading the second half of a dint stat: dint has an address 30.0 and it uses 4 bytes. I need to read 32.0 and not 34.0 ... so how can that be possible without defining that exact address at FB call? The only thing that I would like to be defined at FB call is: input s5time, output s5time and multiply factor - so it is simple to use.
sakal123 Posts: 29 Rating: (0)
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11/23/2011 2:59 PM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 8/31/2025 Posts: 6874 Rating: (1368)	sakal123 I just have a problem reading the second half of a dint stat: dint has an address 30.0 and it uses 4 bytes. I need to read 32.0 and not 34.0 ... so how can that be possible without defining that exact address at FB call? Dear sakal123 , Indirect addressing would be a great help to access local variables inside FB and while FB called as Global variable.Check the following link for more information on "Indirect addressing". STEP 7 -- Creating S7 programs -- Indirect Addressing Best regards, Hamid Hosseini
	Demo Channel on Youtube
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11/23/2011 5:33 PM	Rate (0)
miami Platinum Member Joined: 8/31/2005 Last visit: 9/12/2025 Posts: 2198 Rating: (331)	Due I don't know what is in your marker words, I cant answer. I attached a file, that shows how I would make a FB that multiplies a time with a factor. Attachment FB1.zip (322 Downloads)

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11/23/2011 10:15 PM	Rate (0)
Marciano Bronze Member Joined: 4/30/2007 Last visit: 6/17/2025 Posts: 231 Rating: (23)	Hello sakal123 One alternative is the use of TEMP variables, and in this particular need you could "split" a Local Word for you conversion, see in the attached example I hope this works Marciano Attachment UseTEMP.JPG (317 Downloads)

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11/24/2011 1:12 AM	Rate (0)
Marko Bursic Platinum Member Joined: 9/8/2009 Last visit: 7/17/2023 Posts: 1410 Rating: (154)	you can use pointer and do the same as it was global variable.Lets say that you have a variable named Marker of type dint in STATand you want to access a word of this dint. L P##Marker // pointer LAR1 // store in adress register AR1 L DIW[AR1,P#2.0] // load word located two bytes after begining of Marker T#LoWord //store in other variable of type int or word (16bit) L DIW[AR1,P#0.0] T #HiWord Even if you add variables on begining or if you add input vars, the addresses in instance datablock will change their absolute address, but you will olways get the right result, you can program using symbolic names only. DIW means access of instance data block -word, you can use DID-double, DIB-byte, DIX bit Is this what you were searching for?
	Last edited by: Marko Bursic at: 11/24/2011 1:40 AM
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11/24/2011 8:21 AM	Rate (0)
fritz Diamond Expert Joined: 10/7/2005 Last visit: 9/10/2025 Posts: 3049 Rating: (1062)	sakal123 Here is the part of code I have problems with (LAD): MD312 -> ROUND -> MD316; MW318 -> I_BCD -> MW320 Hello sakal123 miamialready showed you very nicely how to handle the S5Time format, in case you still need an answer for your original problem, Isuggest you keep it as simple as shown in the attached pic. The "trick" is that the "ITB" command (Integer to BCD) only evaluates accu 1 L (the low word of accu 1) which of course has the same contents as you have in"MW318" in your original program. As such thereis no need to try to acccess part of an Instance DB DINT, nor do you need to go down the path of indirect addressing (for which you would also have to take the AR2 offset into account in a Multi InstanceFB by the way). The logic in NW2 can also be done in LAD or FBD, just make sure you untick "Type check of addresses" (see Options menu --> Customize --> LAD/FBD tab). One last thing, I'd use TEMP variables for any intermediate results instead of STAT's. I hope this helps Attachment FB example.jpg (260 Downloads)
	Cheers fritz The advice and opinion given in this thread is that of the author and does not necessarily reflect the views of I S Systems Pty Limited. To find out how I S Systems can help you with your automation needs please visit www.issystems.com.au.
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11/24/2011 2:46 PM	Rate (0)
sakal123 Posts: 29 Rating: (0)	Thank you all for now! You have been really helpful!
sakal123 Posts: 29 Rating: (0)
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This contribution was helpful to 1 thankful Users fritz

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