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Minimum cycle time for safety analog input

Created by: RosDA at: 5/29/2014 12:43 PM (7 Replies)

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5/29/2014 12:43 PM	Rate (0)
RosDA Member Joined: 5/29/2014 Last visit: 7/26/2023 Posts: 3 Rating: (0)	Dear All, I have to read, every 50ms at maximum, a signal coming from a safety Pressure transmitter. The safety transmitter should be connected to a failsafe analog input card (Model: 6ES7 336-4GE00-0AB0). What is the mimimum cycle time between two measurement that is possible to achieve with this F-AI card? Thank you very much for Your support. RosDA

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5/29/2014 12:47 PM	Rate (0)
S7 AUTOMAN Posts: 515 Rating: (56)	RosDA Dear All, I have to read, every 50ms at maximum, a signal coming from a safety Pressure transmitter. The safety transmitter should be connected to a failsafe analog input card (Model: 6ES7 336-4GE00-0AB0). What is the mimimum cycle time between two measurement that is possible to achieve with this F-AI card? Thank you very much for Your support. RosDA use this analog reading function in an interrupt OB which executes at every 50 mS. is that what you require?
S7 AUTOMAN Posts: 515 Rating: (56)
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5/29/2014 1:28 PM	Rate (2)
olloy Silver Member Joined: 8/27/2010 Last visit: 6/3/2022 Posts: 417 Rating: (37)	Hi! For detailed information of configuring failsafe AI-reading, please refer tothismanual. English is not native for me, but if I understood you question correct, you mean monitoring time and in is possible to configure it according with manual: F_monitoring time 0...65535ms Default 2500ms //Monitoring time for failsafe communication between the CPU and the F-AI. You can change monitoring time to desired value with hardware configuration tool. Refer to same manual, page 21. Note: On the Siemens Support website aspreadsheetis available which aids users in calculating failsafe monitiring times.
	Last edited by: olloy at: 5/29/2014 1:33 PM link corrected
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This contribution was helpful to 3 thankful Users UMENCHO 0_Einstein metwally mustafa

5/29/2014 3:41 PM	Rate (0)
RosDA Member Joined: 5/29/2014 Last visit: 7/26/2023 Posts: 3 Rating: (0)	Yes, we have to elaborate the logic in a 50ms cyclic OB, so we must be sure that the analog signal is updated at least every 50ms. I am not sure that with the 336-4GE00-0AB0 F-AI card this can be achieved. Regards RosDA

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5/29/2014 4:03 PM	Rate (0)
olloy Silver Member Joined: 8/27/2010 Last visit: 6/3/2022 Posts: 417 Rating: (37)	I am sure) Please refer to same manual again, page 7: In all functional examples the failsafe analog input module SM 336; F-AI 6 x 0/4... 20 mA HART with order number 6ES7 336-4GE00-0AB0 is applied. So everything I told applied to this module.

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5/29/2014 4:13 PM	Rate (0)
Ton Verra Gold Member Joined: 4/20/2007 Last visit: 8/30/2023 Posts: 724 Rating: (40)	Out of curiosity, why do you need the value at such a high rate? 50 ms is 20 value changes a second. Depending on your program, the execution of a F-program can take a lot more time than a regular program. You should keep an eye on that.

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5/29/2014 5:45 PM	Rate (0)
RosDA Member Joined: 5/29/2014 Last visit: 7/26/2023 Posts: 3 Rating: (0)	@ olloy:thanks, I am reading the doc. @ Ton Verra: we use the measurement in a Surge detection calculation for a centrifugal compressor. Best regards RosDA

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This contribution was helpful to 2 thankful Users Ton Verra olloy

5/31/2014 10:37 AM	Rate (0)
Krrish !! Posts: 73 Rating: (6)	Hi, You could refer attached excel sheet 'S7 ftime.xls' for better estimation of minimum cycle time of Safety Analog Input. Regards, Krrish !! Attachment D:\s7ftimeb.zip (210 Downloads)
Krrish !! Posts: 73 Rating: (6)
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