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peak shape recording

Created by: Oscar_83PL at: 5/30/2011 1:25 PM (8 Replies)

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5/30/2011 1:25 PM	Rate (0)
Oscar_83PL Bronze Member Joined: 10/22/2008 Last visit: 7/26/2024 Posts: 369 Rating: (5)	Hello, HW s7-315 My project is to save/record peak shape. Peak is a preasure shape of air inction to barrel. It last about 500 ms (250 ton/ 25 toff). My question is what shell I use to get sample in every 25ms? Is there any analog module with sample time on that level? Maybe you know if there is a sensor appropriate for the problem (with record function)? best regards

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5/30/2011 2:18 PM	Rate (0)
naah Posts: 76 Rating: (8)	Hi, You may use Analog inputs with interrupt capability. One of them is: 6ES7331-7HF01-0AB0. Good luck!
naah Posts: 76 Rating: (8)
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5/30/2011 2:25 PM	Rate (1)
Niranjan Prasad Posts: 691 Rating: (37)	Oscar_83PL Hello, HW s7-315 My project is to save/record peak shape. Peak is a preasure shape of air inction to barrel. It last about 500 ms (250 ton/ 25 toff). My question is what shell I use to get sample in every 25ms? Is there any analog module with sample time on that level? Maybe you know if there is a sensor appropriate for the problem (with record function)? best regards You have to program your block with scanning rate of 25 ms or less than that for your requirement. You can use Interupt OBs for your purpose. See the attachment for setting the scan rate Attachment Cycle_Interupt.gif (92 Downloads)
Niranjan Prasad Posts: 691 Rating: (37)
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5/30/2011 5:31 PM	Rate (0)
gre_m Posts: 947 Rating: (45)	ET200s has module with 1ms Conversion time
gre_m Posts: 947 Rating: (45)
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5/30/2011 6:12 PM	Rate (0)
Aret Posts: 2348 Rating: (264)	Oscar, i would try another HW - not SIMATIC To begin with - can you tell us how much samples should you get in these 500 ms? Think it would be 1000+ to record peak accurate - and S7-300/400 cycle time can't drop to microseconds... Even in case of 100 samples AND if peak measuring is your main task, i would recommend using appropriate equipment - specially designed for this. If this task is add-on for main controlling task - then yes, i would think about SIMATICs...
Aret Posts: 2348 Rating: (264)
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5/31/2011 9:52 AM	Rate (0)
Oscar_83PL Bronze Member Joined: 10/22/2008 Last visit: 7/26/2024 Posts: 369 Rating: (5)	In my opinion about 10 samples in rising and 10 samples (at least) in faling edge. If the peak is 500 ms long there should be enough to get 500ms/20samples = 25 ms sampling time. It is quite quick sampling and for now I am not sure if it is enough. For now I am not even sure if there is a sensor with such fast change ability.

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5/31/2011 11:43 AM	Rate (0)
gre_m Posts: 947 Rating: (45)	ET200S 6ES7 134-4FB52-0AB0 (+/-10V), 6ES7 134-4GB52-0AB0,6ES7 134-4GB62-0AB0 (4..20mA) - 1ms/ channel. Profibus on 12Mbod = 1ms. Profinet - min cicle 0.25ms.Thatdoes notsuit you?
gre_m Posts: 947 Rating: (45)
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5/31/2011 12:14 PM	Rate (0)
Oscar_83PL Bronze Member Joined: 10/22/2008 Last visit: 7/26/2024 Posts: 369 Rating: (5)	Profibus and et200 probably won't stand my demandings. However 6ES7331-7HF01-0AB0 GALVANICALLY ISOLATED, 8 AI, 14 BIT, 0.052MS/CHANNEL, seems to be fine.

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5/31/2011 6:02 PM	Rate (0)
Aret Posts: 2348 Rating: (264)	Oscar, many people already bumped with these 52ns. It BASIC conversion time for ADC - that doesn't mean you'll gain new values each 52ns 25 ms is ok for S7 family, but gre_m is right - ET200S CPU + modules mentioned will give you good performance on the one hand and low-costed medium-flexible system from the other. I would try it in case there are no additional factors to consider. Upd. As for the sensor - i would look for potential sensors first of all.
Aret Posts: 2348 Rating: (264)	Last edited by: Aret at: 5/31/2011 6:04 PM
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