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1s impulses

Created by: ROCLIM at: 1/4/2011 6:46 PM (10 Replies)

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1/4/2011 6:46 PM	Rate (0)
ROCLIM Posts: 42 Rating: (1)	Hi How can I make impulse in each second.i think to and a cpu merker with not of the same address and some pause in cpu to make the impulses possible.I want to use them as a time track in rest of program. Thank you
ROCLIM Posts: 42 Rating: (1)
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1/4/2011 8:56 PM	Rate (1)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 11/10/2024 Posts: 12293 Rating: (2691)	ROCLIM Hi How can I make impulse in each second.i think to and a cpu merker with not of the same address and some pause in cpu to make the impulses possible.I want to use them as a time track in rest of program. Thank you Why not use the rising edge of the 1s Marker bit as a trigger for your application, this would be areliable pulse of small duration. Hope this helps, Daniel Chartier
	Last edited by: dchartier at: 1/4/2011 8:56 PM
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1/4/2011 9:52 PM	Rate (1)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 10/26/2024 Posts: 6852 Rating: (1365)	Why not use the rising edge of the 1s Marker bit as a trigger for your application, this would be areliable pulse of small duration. As I tested the propoesd program ,memory bit of 500ms can create the mentioned effect. [code] A M 100.5 //500 ms pulse FP M 0.1 = M 0.0[/code] regards
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This contribution was helpful to 2 thankful Users dchartier ROCLIM

1/5/2011 9:32 PM	Rate (0)
ROCLIM Posts: 42 Rating: (1)	Thank you dchartier-hdhosseini for suggestion.I want to go beyond the cpu's pulses.I want to make impuses of any time I want, possible any magical solution?
ROCLIM Posts: 42 Rating: (1)
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1/5/2011 10:32 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 11/10/2024 Posts: 12293 Rating: (2691)	Hello Roclim; Have you ever looked at the open-source (free!)library for S7 from OSCAT.de? Amongst other proposed functions you will find CLK-N, which, as described in the Library Documentation (and translated from the German with babelFish): "CLK_N produces an impulse all X milliseconds based on the SPS internal 1ms reference. The impulses are accurately a SPS cycle long and all 2^N is produced milliseconds. The period duration amounts to 1ms for N=0, 2ms for N=1, 4ms for N=2 etc." Note: SPS means CPU. This function would give you a steady 1 ms pulse. There are other functions such as CLK_DIV wich would take that signal and divide it by multiples of 2, up to 256, to produce pulses of different frequency, if you like. The OSCAT documents are in German, which may or may not throw you for a loop, but the online help of the function blocks is available in English, practical when you want to understand the ins and outs of a function. Hope this helps, Daniel Chartier

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1/6/2011 10:25 AM	Rate (1)
Yoga Shankar Posts: 288 Rating: (22)	Dear All, I have tried a different approach. In OB 35, ( which is available in almost all CPU's of the S7 300 and S7 400 range) perform a simple addition. This is to operate on a memory location. Every time OB 35 is executed, increment the value of this memory location by 1. OB 35 is a time interrupt OB. Hence the time in which this memory location reaches 10 will be exactly 1s. ( OB 35 is executed every 100 ms). In OB 1, where we generally write the application program, include a function which compares the value of the memory location with 10. as soon as this comparision gives an "EQUAL TO" result, i.e. the memory location has exactly 10 as its value, take a positive edge. the STL code would be some what like this A( L <MEMORY LOCATION> L 10 >=I ) FP M X.Y // this will be the temporary storage that will have to be used for getting the edge. = "One_Sec_Pulse" A "One_Sec_Pulse" JCN _01 L 0 T <MEMORY LOCATION> _01: NOP 0 The advantage of this method ( as I see it) is that the timing pulse will always be after 1s, no matter even if OB1 is too long.
Yoga Shankar Posts: 288 Rating: (22)
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This contribution was helpful to 1 thankful Users ROCLIM

1/6/2011 11:26 AM	Rate (1)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 10/26/2024 Posts: 6852 Rating: (1365)	Hello This also may help.I have use it before in another post. you can make a adjustable time between small pulses. Time loaded for T1 and T2 (T1+T2) is the adjustable period between each small pulse.Small pulse is on T1,use it or transfer it to a memory as you like.I think this short pulse's duration is reliable enough and lasts at least one scan cycle of CPU. [code] AN T2 L S5T#5S //ADJUST FOR IMPULSE PERIOD SD T1 NOP 0 A T1 L S5T#5S //ADJUST FOR IMPULSE PERIOD SF T2 [/code] I hope this helps in this issue HDHOSSEINI
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1/18/2011 6:41 AM	Rate (0)
Yoga Shankar Posts: 288 Rating: (22)	hdhosseini Hello This also may help.I have use it before in another post. you can make a adjustable time between small pulses. Time loaded for T1 and T2 (T1+T2) is the adjustable period between each small pulse.Small pulse is on T1,use it or transfer it to a memory as you like.I think this short pulse's duration is reliable enough and lasts at least one scan cycle of CPU. AN T2 L S5T#5S //ADJUST FOR IMPULSE PERIOD SD T1 NOP 0 A T1 L S5T#5S //ADJUST FOR IMPULSE PERIOD SF T2 I hope this helps in this issue HDHOSSEINI Dear HDHOSSEINI, I have also used this technique but it has a disadvantage. If the execution time of OB1 exceeds the back to back timer length, the clock pulse becomes irregular. I mean, if the OB1 cycle time is greater than 1s, the 1s pulses counted in a minute will be less than 60. Also, if this is implemented in an interrupt OB, say OB35 (because this is the one OB supported by a large range of CPU's as compared to other OB's of this class) , then the pulse duration is so small, it may not serve the purpose at all.
Yoga Shankar Posts: 288 Rating: (22)
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1/18/2011 7:46 AM	Rate (0)
hdhosseini Diamond Expert Joined: 1/28/2009 Last visit: 10/26/2024 Posts: 6852 Rating: (1365)	Dear Sir Yes this is an obvious draw back of the system.But if your time values are high enough to ignore errors this will be helpful.The method we are proposing here are drafts and need to be customized when used in your final program.I used this method to produce 5 or 10-minute short pulses. As I know, timers run independent of OB1(?) irregular OB1 execution time may exists for the previous (CPU Clock pulses). BR
	Last edited by: hdhosseini at: 1/18/2011 8:01 AM Demo Channel on Youtube
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1/18/2011 7:53 AM	Rate (0)
Yoga Shankar Posts: 288 Rating: (22)	The timers do run independant of the OB. But, the logic for detecting the elapsed time or timer elapse has to be executed in the OB.
Yoga Shankar Posts: 288 Rating: (22)
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