FB_ServerClientConnection

VAR_IN_OUT

VAR_IN_OUT
    hServer         : T_HSERVER;
END_VAR

hServer: server handle. This input variable must be initialized via the F_CreateServerHnd function.

VAR_INPUT

VAR_INPUT
    eMode           : E_SocketAcceptMode := eACCEPT_ALL;
    sRemoteHost     : STRING(15) := '';
    nRemotePort     : UDINT := 0;
    bEnable         : BOOL;
    tReconnect      : TIME := T#1s;
END_VAR

eMode: Determines whether all or only certain connections should be accepted.

sRemoteHost: IP address (Ipv4) of the remote client whose connection is to be accepted as a string (e.g.: '172.33.5.1'). For a client on the local computer an empty string may be specified.

nRemotePort: IP port number of the remote client whose connection is to be accepted (e.g. 200).

bEnable: As long as this input is TRUE, the system attempts to establish a connection at regular intervals until a connection was established successfully. Once established, a connection can be closed again with FALSE.

tReconnect: Cycle time used by the function block to try and establish a connection.

VAR_OUTPUT

VAR_OUTPUT
    bBusy       : BOOL;
    bError      : BOOL;
    nErrID      : UDINT;
    hSocket     : T_HSOCKET;
    eState      : E_SocketConnectionState := eSOCKET_DISCONNECTED; 
END_VAR

bBusy: This output is TRUE as long as the function block is active.

bError: Becomes TRUE as soon as an error has occurred.

nErrId : If the bError output is set, this parameter returns the TwinCAT TCP/IP Connection Server error number.

hSocket: Connection handle for the newly opened remote client socket. If successful, this variable is transferred to the instances of the function blocks FB_SocketSend and/or FB_SocketReceive.

eState: Returns the current connection status.

Example in FBD:

The following example illustrates initialisation of a server handle variable. The server handle is then transferred to three instances of the FB_ServerClientConnection function block.

PROGRAM MAIN
VAR
    hServer             : T_HSERVER;
    bListen             : BOOL;

    fbServerConnection1 : FB_ServerClientConnection;
    bConnect1           : BOOL;
    bBusy1              : BOOL;
    bError1             : BOOL;
    nErrID1             : UDINT;
    hSocket1            : T_HSOCKET;
    eState1             : E_SocketConnectionState;

    fbServerConnection2 : FB_ServerClientConnection;
    bConnect2           : BOOL;
    bBusy2              : BOOL;
    bError2             : BOOL;
    nErrID2             : UDINT;
    hSocket2            : T_HSOCKET;
    eState2             : E_SocketConnectionState;

    fbServerConnection3 : FB_ServerClientConnection;
    bConnect3           : BOOL;
    bBusy3              : BOOL;
    bError3             : BOOL;
    nErrID3             : UDINT;
    hSocket3            : T_HSOCKET;
    eState3             : E_SocketConnectionState;
END_VAR

Online View:

The first connection is activated (bConnect1=TRUE), although the connection has not yet been established (passive open).

The second connection has not yet been activated (bConnect2=FALSE) (closed).

The third connection was activated (bConnect3=TRUE), and a connection to the remote client has been established.

Further application examples (including source code) can be found here: Examples

Requirements