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Calculate Time difference in 4diac [message #1815642]

Mon, 07 October 2019 17:18

ardianto vn

Messages: 31
Registered: May 2019

Member

Excuse me...
I want to calculate the time difference like in the picture.

Ta = the time when the message was sent
Tb = the time when the message was received
T = Ta-Tb.

I think this can be done by recording the CNF event as the sending time and the REQ event as the receiving time. Is this measurement possible in forte 10? If so, how to do that?

Thank you very much

Attachment: IMG_20191008_000843.jpg
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[Updated on: Mon, 07 October 2019 17:22]

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Re: Calculate Time difference in 4diac [message #1815645 is a reply to message #1815642]

Mon, 07 October 2019 18:58

Alois Zoitl

Messages: 1585
Registered: January 2014

Senior Member

If I understand you correctly then yes this can be done easily. With the new 1.11.0 release, which we just uploaded a few minutes ago [1] we introduced the method NOW_MONOTONIC and NOW which gives you timestamps which you can diff using the IEC 61131-3 functions. This you can use in a basic FB. E.g., the alg before CNF logs the send time and the alg triggered by REQ logs the receive time.

[1] https://www.eclipse.org/4diac/en_news.php#en_news_20191007

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Re: Calculate Time difference in 4diac [message #1815646 is a reply to message #1815645]

Mon, 07 October 2019 19:10

ardianto vn

Messages: 31
Registered: May 2019

Member

Thank you very much for the answer...

Then, when should I use NOW_MONOTONIC and when should I use NOW?

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Re: Calculate Time difference in 4diac [message #1815648 is a reply to message #1815646]

Mon, 07 October 2019 19:57

Alois Zoitl

Messages: 1585
Registered: January 2014

Senior Member

NOW is to give you the current time. This may be affect to step changes (e.g., adjusting winter/summer time).

NOW_MONOTONIC gives you a clear monotonic time. In your case I don't think it will make much difference but I think NOW_MONOTONIC may be simpler to use.

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