I have Citect v 5.5 and i want to communicate with a Siemens CPU315-2 DP via a CP 343-1 Indutrial Ethernet card with my PC's Realtek Ethernet card. I have tried almost everything. Does anyone have a solution for my problem? A step by step example could be e-mailed to me at [email protected]

 

To get Citect to talk to Siemens S7 PLCs you need to use the S7NT driver. Unfortunately Siemens will not publish the S7 protocol specifications and thus you need to use the Siemens SoftNet product (which the S7NT driver interfaces to) which you can purchase from your local Siemens distributor.

Have a look at Citect knowledgebase article Q3683 (the KB is available on your Citect CD or from www.citect.com). The help documentation on the S&NT driver may also help.

Regards,

Kelvin

Disclaimer: I am an employee of Citect. This is a personal communication
and should not be considered an official communication from Citect.
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Have you tried the Kepware OPC server for Siemens Ethernet? It doesn't require anything from Siemens to work and it uses your normal ethernet card. Go to http://www.kepware.com

 

Steve,

This is quite a good idea if you don't want to buy Siemens SoftNet, which can be relatively expensive. You won't get anywhere near the same performance you will by using SoftNet and the S7NT driver but it will work quite nicely.

If you only need to talk to a few PLCs (say < 10) and don't need sub second poll rates then this should be an adequate solution.

Kelvin
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Just one thing to add to that. If you want performance and you have 8 or less connections, Siemens has Softnet S7-Lean. Price wise it competes with the third parties. Performance wise nothing beats it.

Ron

 

Hi Kelvin,

We get extremely good performance from the Kepware driver. They allow you to setup multiple links to the PLCs so each PLC can essentially have its own dedicated communication thread. Doing this allowed us to get sub second updates from all PLCs. If you put all the PLCs on a single channel then you are right it will get slower with moe PLCs, but that is just a configuration issue. Right now we are waiting to get a new version which I was told about the last time I ordered that is going to be even faster, they saying three to four times faster but I'll believe that when I see it. Technically its fast enough for us now because the way we have it configured but appprently this next speed enhancement will occur transparenyly to my application. I guess that means I won't have to change my application. We'll see.

I would give it a try if you have never used them, look in the help file there is a section on optimizing the project that talks about getting the best speed.

 

Hi Armand,

try to sniff the protocol with ethereal. You will see it's not complex and very easy to "rebuild". I've sniffed the protocol and made my own communication unit for delphi. So I can read an write to the PLC like I want and it is very performant.

With kind regards
A Friend