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200ms timer in OB35

Created by: nbk at: 1/15/2010 2:52 PM (4 Replies)

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1/15/2010 2:52 PM	Rate (0)
nbk Posts: 197 Rating: (3)	Dear all, The following codes were found in OB35 with the timer engaged for 200ms !Will itget a chance to runfor 200ms considering OB35, whichwill come backafter 100ms? AN T 1 //Se è scaduto il temporizzatore T1, L S5T#200MS //carica il valore di tempo xxx ms in T1 SE T 1 //ed avvia T1 come un generatore di impulso prolungato. NOT //Nega (inverte) il risultato logico combinatorio. JC M001 //Se il tempo è in corso, termina il segmento attuale. L MB 190 //Se il temporizzatore è scaduto, carica il contenuto del byte del merker MB190, INC 1 //incrementa il contenuto di 1 e T MB 190 //trasferisce il risultato al byte di merker MB190. M001: NOP 0 Then, in another FC , bits M190.0 , M190.1 were used to power a hooter / siren? How this works ? Can anyone "break" this into LAD ? regards
nbk Posts: 197 Rating: (3)
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1/16/2010 8:49 PM	Rate (0)
jklm Platinum Member Joined: 12/22/2006 Last visit: 1/25/2022 Posts: 1742 Rating: (303)	Hello, This is what I believe the OB35 is doing (see attachment) But using a timer itself to start it is not so good. I use a M200.0 in between. Why do you not use the system clock for this? Would be better. Attachment OB35.pdf (280 Downloads)
	Best regards jklm Suggestion was helpful? Feel free to rate it.
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1/17/2010 7:28 AM	Rate (0)
nbk Posts: 197 Rating: (3)	Hello jklm Thank youfor the reply.But back to the last part of my post,what is the significance of bits M190.0,M190.1 which are used for the alarm in another FC? The existing OB35 codes are working for the machine (I didn't program it) so I'm just wondering how the extended pulse timer is able to extend for 200ms without being interrupted by OB35 itself? Thanks yet again.
nbk Posts: 197 Rating: (3)
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1/17/2010 11:05 AM	Rate (2)
fritz Diamond Expert Joined: 10/7/2005 Last visit: 6/7/2023 Posts: 2966 Rating: (1025)	Hello nbk nbk ... what is the significance of bits M190.0,M190.1 which are used for the alarm in another FC? They act assimple clock bits. Incrementing MB190 by 1 every 200ms (which is essentially what happens in your code) is a simple way of creating 8 clock bits with the least significant bit being the "base frequency" and the others being 2, 4, 8 ,16, 32, 64 and 128 multiples of it. In you case the individual bits of MB190 behave like this: M190.0: ON for 200ms, OFF for 200ms (400ms "Base frequency") M190.1: ON for 400ms, OFF for 400ms (i.e. 2 x "Base frequency") M190.2: ON for 800ms, OFF for 800ms(i.e. 4 x "Base frequency") M190.3: ON for 1600ms, OFF for 1600ms(i.e. 8x "Base frequency") M190.4: ON for 3200ms, OFF for 3200ms(i.e.16x "Base frequency") etc. nbk The existing OB35 codes are working for the machine (I didn't program it) so I'm just wondering how the extended pulse timer is able to extend for 200ms without being interrupted by OB35 itself? S5 Timers are handled by the operating system which meanstheir time value and status is updated in the background asynchronously and unrelated to theprogram scan. You could also for example start a 10secOn Delay timer in OB100 and it will come true 10 seconds later even though OB100 is only executed once on startup. This does of course not mean that what was programmed with T1 in your OB35 is "elegant"(it is anything but elegant), but it will"do the job" of creating a "sort of" 200ms pulse (with an errorof up to 100ms! in case T1 times out just after OB35 was called and you'll need to "wait" another 100ms to start it again.The "base frequency" of your logic is more like 250ms on average). A simpler solution would have been to get rid of T1 altogether and simple increment MB190 by 1 every call of OB35. This would then createthe clock bits with a base frequency of 200ms (in which caseM190.1 would neededto be used where currently M190.0 is used and M190.2 would needed to beused where currently M190.1 is used). Even simpler (as mentioned by jklm) is of course to use the clock memory bits from the HWconfig (your logic could however have originatedfrom an S5 upgrade where these would not have existed). I hope this helps
	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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1/18/2010 7:50 AM	Rate (0)
nbk Posts: 197 Rating: (3)	Thank you very much jklm and Fritz.
nbk Posts: 197 Rating: (3)
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This contribution was helpful to 1 thankful Users fritz

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