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understand the IEC Timer(SFB4)

Created by: Import-User-1 at: 4/23/2013 9:48 AM (17 Replies)

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4/23/2013 9:48 AM	Rate (0)
Import-User-1 Posts: 3609 Rating: (29)	Import of a Technical Question of the User ursa ursa Hello, Why I don't understand the IEC Timer(SFB4)?
Import-User-1 Posts: 3609 Rating: (29)
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This contribution was helpful to 1 thankful Users starngm2

4/23/2013 10:15 AM	Rate (1)
Marcjan Platinum Expert Joined: 4/22/2010 Last visit: 11/18/2024 Posts: 5697 Rating: (715)	Hello, What is it you don't understand about this timer? Attached example maybe help you. Regards, Marcjan Attachment sfb4.JPG (3715 Downloads)
	Problem solved? Please let us know! Please no technical questions by PM, use the forum sections for your questions.
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This contribution was helpful to 2 thankful Users H-H santhosh sundaram

4/23/2013 10:51 AM	Rate (0)
Raffy Posts: 209 Rating: (2)	Hi, What Part of IEC timer you don't understand?? Basically we use these timers to accomodate the disadvantage of S7 timers... On delay timer hasan output when there is a rising edge and the PT expires....the output duration would also depend on your IN..
Raffy Posts: 209 Rating: (2)
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4/23/2013 3:42 PM	Rate (0)
fritz Diamond Expert Joined: 10/7/2005 Last visit: 11/18/2024 Posts: 3027 Rating: (1057)	Raffy Basically we use IECtimers to accomodate the disadvantage of S7 timers... and apart from having only a limited number of S7 Timers (aka S5 Timers) their the disadvantages are ....?
	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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1/30/2015 6:09 PM	Rate (0)
Mosh Experienced Member Joined: 7/7/2011 Last visit: 11/11/2024 Posts: 88 Rating: (5)	time base is a disadvantage the IEC timers can run for a lot longer than the S7/S5

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1/30/2015 9:10 PM	Rate (0)
William_B Posts: 5225 Rating: (1196)	(why are we back on an old topic?) Mosh time base is a disadvantage the IEC timers can run for a lot longer than the S7/S5 Dear Mosh.. careful what you are suggesting. There was a VERY good reason for having selected a time base. In actual fact it was a brilliant way of conserving memory space and save on processing time. Just for the academic value of it.. have a look at what the footprint is of such software (IEC) timer. You are however right that we have more resolution with the IEC timers and there are many benifits like bein able to create as many timers as what memory allows us. BUT there are properties from the "old" style S5TIMERS that is better that software timers. It very much depends on what resources you have and need. Thank you - the hair is now split in two. [wink]
William_B Posts: 5225 Rating: (1196)
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6/5/2015 8:31 PM	Rate (0)
SiemsImpossible Experienced Member Joined: 3/10/2011 Last visit: 4/27/2023 Posts: 27 Rating: (0)	I also do not understand the iec timer. There is no mention of EN in the help file, and when I put in a db # it turns red.

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6/5/2015 9:47 PM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 10/26/2024 Posts: 6852 Rating: (1365)	Some points to share: EN and ENO is part of general character of all FC/FB/SFC/SFBs in STEP 7. Perhaps you will find a point regarding to this fact in STEP 7 online manual or here (HD_Cases on BR-EN/ENO Mechanism). About the DB number you assign to it , it is matter of correct syntax and place where you call the IEC timers.Upload a snapshot of your problematic assignment! I hope these comments help you! hdhosseini Attachment DB4.jpg (1373 Downloads)
	Last edited by: hdhosseini at: 6/5/2015 9:51:54 PM Demo Channel on Youtube
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6/7/2015 4:36 PM	Rate (0)
Piotr.M Platinum Expert Joined: 6/24/2013 Last visit: 11/18/2024 Posts: 1652 Rating: (426)	Best would be SFC /not SFB/ timer with REGISTER input (dint) which must be STAT or Marker. it could be based on TICK COUNT and this way every instance needs call + 4byte variable. Have developed one and it works nice. You can use bit smaller range i.e. 21days and have special values for DONE and OV (ET value would saturate at OV)

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6/29/2015 8:35 PM	Rate (0)
igor62il Experienced Member Joined: 5/27/2012 Last visit: 6/26/2024 Posts: 177 Rating: (0)	Helo friends.Just for understanding-For use SFB 4 TON for example, I must associate this timer with any DB?This is correct?I must use DB? Thanks.

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