Hello, 

I am dealing with something I think is not possible to execute. So I thought to give a shot and ask for help. 

I have S7-1500 setup with AS-Interface gateway from Bihl+Wiedermann and this attached to hardware which sends I/O back

What I want is to write a C# application which must be able to connect to the PLC (not directly) but via the AS-I gateway. In other words, I need to somewho implement AS-I gateway in my c# application. The PLC needs to know that it is connecting to AS-I and not an C# application, if the PLC can't find the ASI, he simply won't start.

Now, I know you can use libs such as Snap7 or other to connect to the PLC, but this is not the way I want it to be. I need to "fake" the PLC but telling it it is connected to AS-I (which must be implmented in my C# app). 

Is it possible to do this? 

Any help would be much appreciated

Thank you! 

Hello,

for first give yourself question about possible interfaces on that Gateway, via you can probably establish connection from your app? Give info.

Update: but I must say that I don't understand exactly what you want implement. Why PLC need that your C# app, PLC can via some way know from AS-i gateway about connection.

Hello Duris, 

Thanks for your time.  Please, let me clear things up. I have added a simpel drawing which might give a little more insight what I am asking for. 

I am simply trying to communicate with the PLC without going around the ASI gateway. Using Snap7 men can establish direct communication with PLC. But this is not the case here.

Is there a way to implement an ASI gateway function in my C# app  so that I can establish connection with the PLC. 

Hopefully the drawing could explain a thing or two. 

Hello,

sry but still I don't know answer from you, why you need connect to PLC via that Gateway?? That schema is clear me, but your idea not. Your app C# connection is like connection to server to read some data from Gateway (status,...).

Hello Duris, 

I am simply trying to implement ASI profinet protocol in my C# application. This will be the first step. The seocnd step will be reading the GSD-file in my C# app so that the PLC "knows" that he is talking to the gateway, but actually is not. 

So to sum it up. 

1- implement AS-i profinet protocol 

2- read the GSD-file ( I have this already)  so that the PLC identifies my c# app as ASI 

This to read the I/O of the ASI.  The gateway in the schema gets all the I/O (such as status, sensor, etc..)

The C# will serve as Simulation app. At the end you can see the C# application as man-in-the-middle approach. 

Hello,

hmmm this looks like big challenge. Because I don't know internal message format of data flows in AS-i, my help here probably ends, simply if I'm right I don't realy don't know if someone can help you here. Only question, is this possible problem known to you? Because if it's like I think, you need to know all internal messages for data Exchange via AS-i. Give info pls.

Hello Duris, 

This project is my final graduation project which starts with research (what I am doing now) and finding solutions. This is indeed big challenge. I was thinking to wireshark the PLC and the ASI gateway to have a peek at the data exchange back and forth. 

But hopefully you understand the concept now. If this is not possible, would you recommend me another approach on doing this? I simply need to connect to the PLC using ASI profinet protocol, to send information back and forth to the PLC. 

Hi!

    You should get familial with the Profinet interface, since the gateway is seen by your CPU as a Profinet I/O device. 

https://support.industry.siemens.com/cs/ww/en/view/24057268

https://profibusgroup.files.wordpress.com/2013/01/w4-profinet-frame-analysis-peter-thomas.pdf

Hello,

hmmm very intresting on other side. I agree probably with you about hacking that comm frames, but if you'll have that frames, same they probably say to you nothing. Can you say in which stage of your research are you now? What is known to you now? Really I don't know recommend something to you now, maybe other guys here.

Hello, 

Thanks for helping out. I am still at the very beginning stage of my research. Little to nothing is yet know to me. I need to dig futher into this world. Having me always worked on high-level programming is quite a challenge to switch to low-level for this one. 

If anyone has any other ideas. Please share.