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Initializing variables?

Created by: RichardSapp at: 8/20/2011 12:40 AM (5 Replies)

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8/20/2011 12:40 AM	Rate (0)
RichardSapp Posts: 24 Rating: (1)	Hello! Could someone please explain me how to initialize variables ? I need to make sure that each time that I run a function block or when I run the software for the very first time all the variables must be set to their initial values...I guess this is a basic question... but this is frustrating me! Thanks in advance!! ------------------------------------------------------- Edited: Im working with CPU 1214C. The closest I get to solve this problem is shown in the pictures below. When I try to set up the initial condition the field is not active... see attachment 1.jpg and 2.jpg I am also trying to initialize local variables doing this way: see attachment 3.jpg But it is not working... i find some strange behaviors in the local variables... for sure Im doing wrong here!!!!! Attachment pictures.zip (361 Downloads)
RichardSapp Posts: 24 Rating: (1)	Last edited by: O_Moderator at: 8/21/2011 10:43 AM pictures transferred to attachment Last edited by: RichardSapp at: 8/20/2011 9:16 PM
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8/20/2011 5:33 PM	Rate (0)
smiffy Platinum Expert Joined: 1/17/2007 Last visit: 11/27/2023 Posts: 1526 Rating: (527)	The way I would do it is to add some code to the restart OB's, that set the variables to your required initial values. The restart OB's are:- OB100 - Warm restart OB101 - Hot restart OB102 - Cold restart Not all CPU's support all the restart types. You should consult the manual for your chosen CPU to see what restart OB's are supported.
	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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8/20/2011 9:20 PM	Rate (0)
RichardSapp Posts: 24 Rating: (1)	Hello and thanks for answering! Do you think it is possible to do what you suggest when using a 1214C? Regards PD: I updated my first post with some additional information.
RichardSapp Posts: 24 Rating: (1)
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8/22/2011 5:11 AM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 11/29/2023 Posts: 13945 Rating: (2277)	Yes, all the S7-1200 projects I've commissioned all have the 1214C PLC. For me the simplest approach was to create a global DB for values that need to retain values and initialize at startup. Oddly enough, I call that DB by the name of RETAINED_DB :) For PLC tags it is more difficult. For FB/FC local tags, it becomes more difficult to find a consistent approach. For the RETAINED_DB, you can add all kinds of structures and tag data types. Works very well, but it does make it more difficult to just copy the FB/FC and get everything you need to make it work in another application so you lose some portability.
	science guy
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8/22/2011 1:27 PM	Rate (0)
Denilson Pegaia Platinum Expert Joined: 9/23/2005 Last visit: 11/29/2023 Posts: 4277 Rating: (1377)	Hi initial value is just avaliable to FB, not FC. The FC just take parameters from the In / Out / Inout. Temp values has no intial value because they are recicled by operational system on each block call/end.
	Denilson Pegaia Siemens Industry Sector Technical Support
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8/23/2011 6:47 PM	Rate (0)
RichardSapp Posts: 24 Rating: (1)	Many thanks!
RichardSapp Posts: 24 Rating: (1)
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