3/27/2009 10:10 AM | |||
Posts: 33 Rating: (1) |
Dear I have the excel file to calculate safety monitoring time following the link http://support.automation.siemens.com/WW/view/en/23926783.
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Last edited by: SAGITAR at: 3/27/2009 10:13 AM |
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3/28/2009 9:05 PM | |
Joined: 12/22/2006 Last visit: 1/25/2022 Posts: 1742 Rating: (309) |
Hello, First you must be sure that the program is not longer that the call of OB35 (that you leave enough time for the cyclic program). And the blocs handling the I/O are time consuming. The third Tab of the excel sheet allows to compute the max reaction time (max time between change at a physical input and reaction on the physical output). The change must reach the CPU, the program must be executed and the resultreturned to the output. The max reaction time depends on the runtime of the safety program. |
Last edited by: edr at: 3/28/2009 9:10 PMBest regards |
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3/29/2009 5:33 AM | ||
Posts: 33 Rating: (1) |
, sorry, I can't understand. CPU processes the program in the OB35. CPU will stop or alarm if the program's time is longer than that of call OB35. so, if OB35 calles F-Call, the runtime of group must be within the time of call OB35. the runtime of group+time of call OB35>time of call OB35, so that theCPU will stop or alarm. so, I think the item
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3/30/2009 7:57 AM | |
Joined: 3/24/2009 Last visit: 7/9/2024 Posts: 535 Rating: (112) |
Dear SAGITAR, to be sure, that we talk about the same time, here a short summary about the monitoring-time: > What is the F monitoring time? > Time monitoring of message frame updating in the > PROFIsafe protocol requires a valid current > message frame from the partner within a parameterizable monitoring time. The failsafe-program will update the PROFIsafe-protocol and you have to tell the system how much time between one update and the next may elapse. The minimum time for this is the cycle-time for your OB. But as you do not have a guarantee, that the update is always done at the same position of the failsafe-program (especially for CPU-CPU-comunication), you should at least add the runtime of your failsafe-program. As mentioned above you could add the cycle-time of the OB twice, because this would be the sum of one time the OB-cycle-time and the maximum allowed F-runtime-group. Regards, yy1 |
3/30/2009 8:15 AM | |
Posts: 33 Rating: (1) |
first, thank you yy1. I had read the calculation formula from profisafe specification. and Iget theanswercombined with your answers. thanks again! |
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