Dear all,

I have a few questions about the sysSocket library and about the TCPip example found in the website download area.

First I will tell you guys what I want to reach.
I'm trying to setup a communication between a plc (Wago module) and a computer (windows 7 / application). I searched for some while and i found the sysSocket library. I'm not sure for 150% but with this library my goal should be reached, not?

1) I download and wanted to test the TCPip example (in simulation mode) to get more knowledge about the use of the socket library. But i came with a first disappointment, it didn't work. I couldn't get connection between the Server and Client. If run the program step by step i see the SysSocketOption() gives me a FALSE and the SysSocketBind() also gives me a FALSE, so it doesn't go further. Further debugging doesn't gives me a working example.

What did I do? Load the project, Set simulation mode on, click online, click run, start the client and the server. IP= 127.0.0.1 port 4444 default settings of the example.

2) Is working with sockets the best way to transfer some data (not much) over the network? Like I told before, from the PLC to a Computer and visa versa?

Kind Regards,
Glenn

HI all,

I managed to get the socket communication working. Only i run in to a small but important issue.

When i send some chars to my tcp server (PLC), I split up my received chars. The first char followed by nothing and the next run in the repeat loop the other chars.

For example:
I declared a variable "" when I send these chars "+0011-" to my PLC I get the folowing.
abyRecvRaw[1] = +
abyRecvRaw[2] = nothing
..
abyRecvRaw[8] = nothing

the secund repeat gives me this
abyRecvRaw[1] = 0
abyRecvRaw[2] = 0
abyRecvRaw[3] = 1
abyRecvRaw[4] = 1
abyRecvRaw[5] = -

As you can see the send data isn't received well. it should be like this.
abyRecvRaw[1] = +
abyRecvRaw[2] = 0
abyRecvRaw[3] = 0
abyRecvRaw[4] = 1
abyRecvRaw[5] = 1
abyRecvRaw[6] = -

You can find a peice of code below.
Before the core parts you find **, so you can easy track the receiving data part.

If any of you guys have some explaination for it, it should be great.

Kind Regards,
Glenn

Variables

abyRecvRaw: ARRAY [1..8] OF BYTE;

(*Open listening socket*)
   IF diSocket = SOCKET_INVALID THEN
      diSocket := TcpServerOpenSocket(uiPort, 1);
   ELSE
      (*Wait for a client connection*)
      IF Client.diSocket = SOCKET_INVALID THEN
         Client := TcpServerWaitForConnect(diSocket, 250);
      ELSE
         (*Receive*)
         REPEAT
**            diReceived:= TcpReceiveData(Client.diSocket, ADR(abyRecvRaw), SIZEOF(abyRecvRaw), 10);
            IF diReceived < 0 THEN (*Problem occured*)
               CloseSocket(ADR(Client.diSocket));
               Client.stIPAddress:= '';
               LifeSignTimeoutTimer(IN:= FALSE);
            ELSIF diReceived > 0 THEN (*Something received*)
               LifeSignTimeoutTimer(IN:= FALSE);
               bReceived:= TRUE;
               IF NOT (diReceived = 1 AND abyRecvRaw[1] = 0) THEN
                  (* Received Protocol data to Protocol_Reader *)
                  abyRecv:= Filter_Protocol_Data(abyRecvRaw);
                  (* Check and Set protocol *)
                  Result := Protocol_Reader(abyRecv);
               END_IF
            END_IF
         UNTIL
            diReceived <= 0
         END_REPEAT;

TCPReceiveDAta (FUN)

IF SocketIsReadable(diSocket, diTimeout) THEN
**       TcpReceiveData:= SysSockRecv(diSocket, pbyData, diDataSize, 0); (* Returns 0 if gracefully closed or -1 for an error*)
   IF TcpReceiveData <= 0 THEN
      TcpReceiveData:= TcpReceiveData - 1;
   END_IF
END_IF