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4/15/2010 11:07 AM | |
Posts: 24 Rating: (0) |
Hello, Please I want to know the difference between functions (FCs) and function blocks (FBs) in program excuting and memory access ??? Best Regards |
4/15/2010 3:49 PM | |
Joined: 9/27/2006 Last visit: 4/26/2024 Posts: 12257 Rating: (2665)
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Hello masobhy; As far as I know, there is very little difference between FBs and FCs as far as program access is concerned, they are simply called by a hiher-level block when needed. As far as memory usage, FCs use global data blolcks (available to all the program blocks whenever needed) and FBs have an attached, dedicated Instance DB that allow variables declared as "stat" to be available at all times to other program blocks. Here are a few threads that you might want to look at for more information: Threads on the differences between FC and FB: FAQ: difference between global DB and instance DB: http://support.automation.siemens.com/WW/view/en/15360455 Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 4/20/2010 6:46 PM |
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