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looking for convert FB from CHAR to Real or Integer

Created by: manassas at: 4/12/2006 6:00 PM (9 Replies)

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4/12/2006 6:00 PM	Rate (0)
manassas Posts: 51 Rating: (0)	Hi, I am getting data from serial channel of CP341 of S7314 in char and moving them into DBs. The data format is 123456.7 in ascii -char- format. sometimes . period place may change that means 12345.6 I can do it with buch of codes (using lots of DB and FCs) my question is how can I do this simply I mean that is there any ready function block for it. like convert char ascii to reall or integer if so where :( Could somebody tell me which FC or FB on S7 300 PLC do I have to use to convert char ascii to real or integer? In S7I have used the ATH. Do I have to create my own FC or is there a FC in the S7 300 library ready to use?. Thanks in advance,
manassas Posts: 51 Rating: (0)	Last edited by: manassas at: 4/12/2006 6:08 PM
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4/15/2006 8:58 PM	Rate (0)
Late Platinum Expert Joined: 1/7/2006 Last visit: 11/17/2023 Posts: 2705 Rating: (318)	Hi Manassas, The easiest way to do this is check the ASCII-character, by subtracting 48 you will have the number and then multiply with the decimal. [:o] Example: "9""8""3"ASCII <57><56><51>ASCII(decimal) (9)(8)(3)Decimal \|\| \| \| \| +-- 3 * 10^0 = 3 \| +------ 8 * 10^1 = 80 +------------ 9 * 10^2 = 900 ___ + 983 (decimal) [;)] If it is a floating number then you have first to detect where the "." is located. [:blush:] If it is a REAL then direct use a REAL to math the results.
	I hope that the answer will help, if you have still questions, don't hesitate to ask me. All the best, Late Never say never, think in solutions, not in trouble......
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4/19/2006 1:19 PM	Rate (0)
manassas Posts: 51 Rating: (0)	hi late, What if number is 13 digits? Thx for the valuable info.
manassas Posts: 51 Rating: (0)
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4/19/2006 3:00 PM	Rate (0)
Denilson Pegaia Platinum Member Joined: 9/23/2005 Last visit: 12/9/2024 Posts: 4358 Rating: (1454)	Hi, in the standard library / IEC Function Blocks there is a FC 58 (String to integer) and a FC 59 (string to real). I think you can use the FC 59 if your telegram follow a IEC standard. Else, you can split your string in two and use the FC 58 to convert the numbers before signal and after signal.
	Denilson Pegaia Siemens Industry Sector Technical Support
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4/24/2006 3:39 PM	Rate (0)
manassas Posts: 51 Rating: (0)	Sory but I do not have FC58. in mine library ends atFC40. Do I need to update? If so from where? Thx. I use Simatic Manager V5.3 + SP3
manassas Posts: 51 Rating: (0)	Last edited by: manassas at: 4/24/2006 3:46 PM
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4/25/2006 12:12 PM	Rate (0)
Wizard Diamond Member Joined: 4/24/2006 Last visit: 12/9/2024 Posts: 8781 Rating: (1172)	Hello Manassas, The functions are FC37, FC38 and FC39. But pay attention you have to use Strings. This mean you have to chance the type Char to a type String, before you can use these functions. And when you have a '.' in the DB the functions will return a '0' instead of a correct number.

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4/29/2006 8:57 PM	Rate (0)
manassas Posts: 51 Rating: (0)	Thx.
manassas Posts: 51 Rating: (0)
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5/31/2014 7:17 PM	Rate (0)
Nakul Posts: 1 Rating: (0)	Hello everyone, Same thins happening with me, the "." comes bt FC can't show it n give error. I want that "." to show the weight,let's say 9.153kg, I'd grouped the string bt I'm unable to show ".", plz help me for this issue.
Nakul Posts: 1 Rating: (0)
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5/31/2014 7:21 PM	Rate (0)
IBN-Service Posts: 8946 Rating: (999)	You can not watch strings, you only can watch an array of chars. Best way is to monitor the string variable by using a HMI, i.e small WinCCflex project.
IBN-Service Posts: 8946 Rating: (999)
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11/24/2014 9:28 AM	Rate (0)
amcorgd Experienced Member Joined: 9/3/2010 Last visit: 11/14/2024 Posts: 17 Rating: (3)	I was also looking to convert ASCII char to real, and bumped into this thread. Just to share that there is this FC104 from Siemens sample conversion project: String_R, which you can download from this link. http://support.automation.siemens.com/WW/view/en/10913338 Our data comes in ASCII character with one decimal point. Assume you had the char DB ready, this FC104 works smoothly as long as the start address and length is keyed in correctly, at least for our case...

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