3/19/2016 1:30 PM | |
Joined: 9/27/2006 Last visit: 9/19/2024 Posts: 12282 Rating: (2684)
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Hello Mahmoud; If you search for your CPU part number in Product Support and open the Technical Data, you will find that your CPU is equipped with a RTC (real-time clock) with a resolution of 1ms, which can sound impressive. However, look at this attachment from Hans Berger, taken from an online extract: So you can expect a time drift of more than 8,5 s per day in normal circumstances... If precise time measurement is required in your project, it is normal to synchronize the CPU time with an external time master (onre you can trust, of course), a PC, another PLC, an HMI station, a Profibus or Ethernet partner in the project, or a NTP master (using SiClock, for example). Have a look at this collection of FAQs on time synchronization, find a solution that matches your project, and look at how your CPU's clock can be regularly synchronized to avoid regular time drift: Time synchronization - Time synchronization in the automation environment https://support.industry.siemens.com/cs/ww/en/view/86535497 Hope this helps, Daniel Chartier |
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3/19/2016 8:23 PM | |
Joined: 9/27/2006 Last visit: 9/19/2024 Posts: 12282 Rating: (2684)
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Hello Mahmoud; Not in detail. Most of the information available on the backup battery support concern the RAM memory and (in small detail) the real-time clock. Any other support function is not described in the available manuals from Siemens. You can look at the following FAQ which resumes the available information on backup batteries for the S7-400, specially if you follow the links pointed out at the bottom of the document: How great is the power requirement (from the backup battery) of the modules to be backed up at "Power Off" and what is the relationship between the backup current and the length of the backup time? https://support.industry.siemens.com/cs/ww/en/view/17900782 Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 3/22/2016 1:38:40 AM |
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This contribution was helpful to1 thankful Users |
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