3/17/2013 6:57 PM | |
Joined: 9/23/2005 Last visit: 3/31/2025 Posts: 4406 Rating:
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Hi, The manual “SIMATIC S7-1500, ET 200MP, ET 200SP Cycle and response times” Overview There is a suptil difference between cycle time and response time: - Cycle time comprises the image update time and OB execution time. -Response time is the time from then incoming of an input signal up to the response at an output signal. The cycle time is a part of the response time. The response time includes also module read/write times, communication over networks and inside decentral periphery (IO module / IM times). Many factors that are taking account on the response time should be counted once for the best case or twice for the last. Reason: it is possible that an incoming signal could come an infinitesimal instant before (or after) the input is read. If it comes after, that means that the software will just recognize the signal at next program execution cycle. TIPs: Central x distributed IO As in the manual, for cycle time calculation, the update time for central IO modules is something about 90 micro seconds / word x 0,5 micro seconds / word for IO modules in PROFIBUS or PROFINET. That is a fact, but it could leave to a miss understanding that the response time of central IO modules are always slower as distributed IOs… It is necessary to understand that the update image by PROFINET / PROFIBUS is quickly because in the distributed IO case, the information pooling of IO modules is done by IM and not by the CPU itself. So this time doesn’t retard the OB execution time (cycle time) but it should take in account in the response time. The use of distributed IO with several ET 200, however gives the possibility to make this pooling in parallel, by the several IM, and this could leave really to quickly response times. On other hand, each PROFINET telegram has headers, that waist timi, so the greather number of distributed IO, greather the overheads. Each case should be calculated individually, however it is possible to take some general tomb rules: General response time for a CPU + central rack IOs < CPU + 1 x periphery distributed IOs General response time for a CPU + central rack IOs > CPU + split in several distributed IOs / central rack IOs Generally also, alone, each factor is located in the size of micro seconds, and so, they have not significant influence in the general automation tasks. However of time critical cases, response time for each possible configuration should be calculated to assure that the best solution are take. Communication Communication tasks are processed as priority 15. That means: - OBs with priority <15 are affected by communications tasks - OB with priority >15 are not affected by communication tasks (on other hands, OB with priority >15 could retards communication tasks). |
Last edited by: Pegaia at: 3/18/2013 10:43 AMDenilson Pegaia |
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3/22/2013 3:12 PM | |
Posts: 14 Rating:
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Hi, I was comparing ET200S HighSpeed with HighFeature to learn the difference between them when I run into term "Response time" in their manuals. There is a formula to calculate response time based on numbers and types of operated modules. However it is still not clear to me what does it mean... Especially for ET200S HF because the formula contains 390us base + modules dependant time but minimal Profinet IO update rate is 250us. Does this mean that HF is able to communicate via PN IO each 250us but is not able to gather (refresh) data that fast? I'm sorry but I didn't find answer for this question in your post... When I followed the link there was some Response time counted even with processing time of user PLC code... Are there more "types" of Response time? I've got a mess in these terms.. matus
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3/22/2013 5:45 PM | |
Joined: 9/23/2005 Last visit: 3/31/2025 Posts: 4406 Rating:
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Hi, You are right: the Response time is the summ of all things between the input field device to output field device. This take in account also the time "waist" internally in ET200.and if some data is not avaliable (or clear) the calculation is unpossible. The focus here is the S7-1500 itself and not the "peripheric" devices. In the case of ET200S data, I suggest you open a new post, in the Decentral Periphery conference, asking directly for the internal time for ET200S. |
Last edited by: Pegaia at: 3/23/2013 10:21 AMDenilson Pegaia |
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3/23/2013 10:21 AM | |
Joined: 9/23/2005 Last visit: 3/31/2025 Posts: 4406 Rating:
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Hi, to better unterstand the theory, here there is a practical example: Buttom -> DI module (ET200S)-> IM151-3PN (ET200S)-> PROFINET->S7-1511->program (on open contact + one coil)->DO (central rack) -> main contactor 1x Buttom delay (0 ms - as definition) 1x DI Input delay (4DI DC24V HF 6ES7131-4BD01-0AB0 http://support.automation.siemens.com/WW/view/en/25388101 page 10) = set as 0.1 ms => worst case = 0.15 ms 2x Time for IM read the signal (IM151-3 PN HIGH FEATURE 6ES7151-3BA23-0AB0 http://support.automation.siemens.com/WW/view/en/30609285, page 55): Response time [μs]: 390 + Maximum of (380 + 9m + 11do) or (24m + 40ai + 80t) + Maximum of (120 + 9m) or (24 + 9do + 40ao + 80t) In our case: m=2 (PM-E+DI), do=0, ao=0, ai=0, t=0 => 390 +max [(380+2*9+0), (24*2+40*0+80*0)]+max[(120+9*2),24+9*0+40*0+80*0)= 390+max[380,48]+max[138,24] =390+380+138=908 μs = 0,908ms 2x PROFINET IO time =2ms (defined by programmer) 2x CPU internal time (“SIMATIC S7-1500, ET 200MP, ET 200SP Cycle and response times” http://support.automation.siemens.com/WW/view/en/59193558) as page 25: Internal response time = 2 x transfer time of the process image inputs + 2 x processing of the user program + 2 x transfer time of the process image outputs Transfer time of the process image inputs, as page 16: 35us*1+0,5μs*1 = 25,5μs= 0,0255ms Response time for program: 1 open contact + 1 coil = 2 binary instruction = 2 *60ns = 120ns=0,12μs=0,00012ms Transfer time of the process image inputs, as page 16: 35us*1+9 μs*1 = 42 μs = 0,042ms Total CPU internal time without communication last = 0,0255ms + 0,00012ms + 0,042ms = 0,06462 ms Communication load = 15% (defined by programmer) Total CPU internal time with communication last 0,06462 ms *100/(100-15) = 0,076 ms 1x DO Output delay (6ES7522-1BF00-0AB0DQ 8X24VDC/2A HF http://support.automation.siemens.com/WW/view/en/59193089 pg22) = 500 μs = 0,5ms 1 x main contactor (?... I define as 5ms) Total response time = 1*(0+0,15)+2*(0,908+2+0,076)+1*(0,5+5)= 11,618 ms |
Last edited by: Pegaia at: 3/23/2013 1:08 PMDenilson Pegaia |
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This contribution was helpful to
4 thankful Users |
3/25/2013 10:18 AM | |
Posts: 14 Rating:
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Thank you for clarifying me a few important things. I'll address my further questions to correct conference.
matus |
3/25/2013 10:45 AM | |
Joined: 9/23/2005 Last visit: 3/31/2025 Posts: 4406 Rating:
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Hi, you are wellcome! Don't worry about the post.Sorry,(maybe Iwas unnecessary hard). |
Denilson Pegaia |
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4/9/2013 10:07 PM | |
Joined: 9/23/2005 Last visit: 3/31/2025 Posts: 4406 Rating:
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Hi, The internal response time for ET200MP could be found in the Apendix B of the manual "ET 200MP IM 155-5 PN ST interface module (6ES7155-5AA00-0AB0)" at http://support.automation.siemens.com/WW/view/de/59193106/0/en PS: Thanks for Mr Andreas Kraft for the tip. |
Denilson Pegaia |
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4/25/2013 5:38 PM | |
Joined: 9/23/2005 Last visit: 3/31/2025 Posts: 4406 Rating:
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Hi, I couln't found a documentation about ET200SP. I open a Support Request about it and I was informed that the ET200SP is working more simple. It´s bus is synchronized at thePROFINET clock. Therefore the reaction is constant every 1ms and only the reaction time of the PLC must be added.. PS: Thanks for Mr Frank Meumann for the tip. |
Last edited by: Pegaia at: 4/26/2013 12:03 PMDenilson Pegaia |
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4/26/2013 6:20 AM | |
Joined: 8/31/2010 Last visit: 4/2/2025 Posts: 1524 Rating:
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Hello Pegaia, Is it PROFIBUS clock? |
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4/26/2013 12:02 PM | |
Joined: 9/23/2005 Last visit: 3/31/2025 Posts: 4406 Rating:
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Sorry It is PROFINET, not PROFIBUS. I corrected the open text. |
Denilson Pegaia |
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