Hello Guys!

I'm trying to communicate my robot controler with PLC using TCP server/client.

First what i want to do, is write correct program on PLC, and test it using Herkules program (http://hercules-setup.soft32.com)

In case PLC as server, my code:

PROGRAM PLC_PRG
VAR
        sa: SOCKADDRESS;
   saSize: DINT;
   port: WORD;
   hSocket, hClientSocket :UDINT;
   maxConnections: DINT := 10;
   result: UDINT;
   str: STRING:= 'Hello, Client!';
   str2: STRING(255);
   numberOfBytes: DINT;
   
END_VAR

hSocket := SysSockCreate(SOCKET_AF_INET, SOCKET_STREAM, SOCKET_IPPROTO_TCP, ADR(result));
sa.sin_family := SOCKET_AF_INET;
sa.sin_addr.ulAddr := SOCKET_INADDR_ANY;
sa.sin_port := 999;
result := SysSockBind(hSocket, ADR(sa), SIZEOF(sa));
result := SysSockListen(hSocket, maxConnections);
hClientSocket := SysSockAccept(hSocket, ADR(sa), ADR(saSize), ADR(result));
//SysSockSend(hClientSocket, ADR(str), len(str) +1, 0, ADR(result));
//str2:= '';
//SysSockRecv(hClientSocket, ADR(str2), 256, 0, ADR(result));
//SysSockClose(hClientSocket);
//SysSockClose(hSocket);

I got exception.
And it doesnt work.
I even cannot connect (using herkules).
I just put in herkules 'tcp client' IP adress -> PLC IP, and port 999 (is it right?)
And i cannot connect, and it doesnt ping.

What am i doing wrong ?

This is result:

What does the "green C" mean ?

1) the IP address and port must be converted to network format with SysSockHton* functions:
sa.sin_addr.ulAddr := SysSockHtonl(SOCKET_INADDR_ANY);
sa.sin_port := SysSockHtons(999);

2) saSize must be initialized before performing the SysSockAccept:
In the sa structure will be copied the information of the connected client, so SysSockAccept() must knows the size of the structure passed.
saSize: = SIZEOF(sa);
hClientSocket := SysSockAccept(hSocket, ADR(sa), ADR(saSize), ADR(result));

3) Disable the task watchdog because SysSockAccept is blocking; by default sockets are blocking when created.
The caller task is 'frozen' until someone connects.
Otherwise to prevent the watchdog I suggest you to use the SysSockSelect to check if someone has requested a connection and only then use the SysSockAccept.

The "green C" I think means Constant variable.

Maybe an option is to use the Use Case library: Network.
It has a much friendlier interace than the syssocket library.

See the store for examples.

Moreno hat geschrieben:
1) the IP address and port must be converted to network format with SysSockHton* functions:
sa.sin_addr.ulAddr := SysSockHtonl(SOCKET_INADDR_ANY);
sa.sin_port := SysSockHtons(999);
2) saSize must be initialized before performing the SysSockAccept:
In the sa structure will be copied the information of the connected client, so SysSockAccept() must knows the size of the structure passed.
saSize: = SIZEOF(sa);
hClientSocket := SysSockAccept(hSocket, ADR(sa), ADR(saSize), ADR(result));
3) Disable the task watchdog because SysSockAccept is blocking; by default sockets are blocking when created.
The caller task is 'frozen' until someone connects.
Otherwise to prevent the watchdog I suggest you to use the SysSockSelect to check if someone has requested a connection and only then use the SysSockAccept.
The "green C" I think means Constant variable.

Dear Moreno

Do you have a complete example of a tcp socket server for reading and writing?

Originally created by: KevinR

As TimvH said, please try out the CAA NetBaseSrv "CAA Net Base Services" Library.
You will see - it's much more easier and it's also well documented. You can get it to work in a short time!

The HTTP Client example (http://store.codesys.com/http-client-example.html

Best Regards,
Kevin

aso3964 hat geschrieben:
Dear Moreno
Do you have a complete example of a tcp socket server for reading and writing?

I'm working on a similar project, does anyone have a complete project where a TCP server is configured using Sockets?

Thank you

If you hardware supports CAA NetBaseServices Library, then this may help :
l viewtopic.php?f=11&t=8641 l

danyamian hat geschrieben:
I'm working on a similar project, does anyone have a complete project where a TCP server is configured using Sockets?

I am walking in the same shoes now, have you got any usable resources in this topic? If so, could you share?

Hi all,

Codesys store have a complete Tcp/Ip server and client solution example.

https://store.codesys.com/communication/plc-chat.html m