# libnodave - S7-319 scan cycle time



## MDoty (23 Oktober 2009)

Hello All!

I am using libnodave in a VB.NET project with Visual Studio 2008.
I am trying to remotly monitor the scan cycle time of the CPU but I have not been able to find it in the SZLs.
The libnodave library works great and I am accessing data from the CPU over a ISO_TCP connection.  I have read thru the Siemens manual "System Software for S7-300/400 System and Standard FunctionsSystem Software for S7-300/400 System and Standard FunctionsSystem Software for S7-300/400 System and Standard Functions" but have not found it.

I am not a Step-7 programmer so I am just starting to learn where things are stored in the S7 PLCs.

Thank You for your Help
Mike Doty


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## Thomas_v2.1 (23 Oktober 2009)

Hi,
I'm not really sure of the behavior of all CPUs.

But check SZL ID 0x0222 with index 1.

You should receive one partlist with length of 28 bytes, and in this data:
- at bytes 7/8 the actual/last cycle time
- at bytes 9/10 you get the shortest cycle time
- at bytes 11/12 you get the longest cycle time

There are some additional SZL infos in the Siemens WinAC documentation.
ID 0x0222 is listed there as "Interrupt status", I think it's because the OB80 (cycle time fault) is called when the cycle time is over the limit.
The cycle time limit you should get with index 80.

Thomas


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