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Old August 10th, 2006, 08:02 AM   #1
Esa
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Question Siemens CP343-1 U_SEND & U_RECV and S7 connection protocol

Can you please help me to choice the “best” solution for communication between CPU:s.
I have following kind of system:


I already have created S7 communications between UCP901 and UCP0*1 by using U_SEND (FB8) & U_RECV (FB9). I have selected UCP901 to establish an active communications.

This system was working ok, until I once was forced to download everything to CPU (UCP031). After this action, the communication between UCP901 and UCP031 was not established until I downloaded the network configurations once again to UCP901.

The Ethernet bus was ok, because all the CPU:s were communicating with HMI station.

When I selected CP343-1:s Module Information \ Special Diagnostics \ Ethernet connections I could see yellow semicolon telling us, that there is no S7 connection between these stations. The U_SEND block Error bit was at 1 and Status word at 16H0001. According to Siemens manual this corresponds to a communication problem that might arise from: Connection description not loaded, Connection interrupted, or Connection to partner not establish.

After this incident the communication have been “halted” few times and the only way to get it work seem to be downloading the network communications either to UCP0*1 or UCP901.

Have anyone had similar problems when using U_SEND (FB8) & U_RECV (FB9) and S7 connection protocol?

On this forum you have plenty discussion about using of AG_SEND (FC5) & AG_RECV (FC6) and ISO-on-TCP protocol, might this be more reliable way to do the communications for 300 series CPU:s ?
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Old August 12th, 2006, 02:27 AM   #2
Prince
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I Learnt it by doing I am an eng but had no Siemens training
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This happened to me some time. rationally it must not happen. when I download the hardware configuration some of the time a working S7 communication get corrupted normally I check the connection parameters again in Netpro and download it to each Cpu then I check if it is working or not by monitr if it is not I will do it again. for me it did not took that long...

If the connections are green for you and you still don't have the communicatin we can talk about the step7 but I normally don't go to step7when connections are shown as failed in Step7...
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Old August 12th, 2006, 12:19 PM   #3
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As a practice, use of FDL connections in S7-300 has bigger performanece then S7 connecions. Generally S7 communication functions like GET, PUT, etc. in S7-300 have low performance. FDL can be about 10 times faster (or even more).
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Old August 14th, 2006, 02:44 AM   #4
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Thanks for answers.

The solution, where I need to download the network connection by using NetPro is not acceptable reliability level for me.

My college found one FAQ which might be helpful for me:

Why do sporadic faults occur in S7-300 communication jobs after a CPU Stop-Start?
Link for siemens FAQ:s
http://support.automation.siemens.com/WW/llisapi.dll?query=WHY+DO+SPORADIC+FAULTS+OCCUR+IN& func=cslib.cssearch&content=skm%2Fmain.asp&lang=en &siteid=cseus&objaction=cssearch&searchinprim=0&no deid0=10805868&x=33&y=9



Unfortunately at the moment I don’t have any possibility to test, if this information is helpful for me. But that I can tell that all the DB:s are “Retain” as default in CPU315-2DP.
Maybe in some day I have possibility to test, if this “Non-Retain” property is helping us.
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Old August 14th, 2006, 02:57 AM   #5
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Your desired reliability level is so tough. I am sure that this will not be satosfying for you but one of the systems that I did the same for is working for about 4 yrs with no problem...

Anyhow can you try to reset the CPs ?
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Old August 14th, 2006, 03:10 AM   #6
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Hi!

Yes I can reset the CPs, but It won't help in this case. As I told the only way to get the communication work is downlading the NetPro once again to CPU.

For me the level would be ok, if I could live near by the "process", but in this case I'm livin more than 16h flight time of the target.
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Old August 14th, 2006, 03:19 AM   #7
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I think somebody on site is needed. anyhow I would think it would be OK if you name the country may be somebody near Can help. for sure He is not me. I am living 5hr flight from Finland...

Last edited by Prince; August 14th, 2006 at 03:22 AM.
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