FB_TlsSocketConnect

The FB_TlsSocketConnect function block enables a client to establish a new TCP/IP connection to a remote server via the TwinCAT TCP/IP Connection Server, secured via TLS. If successful, a new socket is opened, and the associated connection handle is returned at the hSocket output. The connection handle is required by the function blocks FB_SocketSend and FB_SocketReceive, for example, in order to exchange data with a remote server. If a connection is no longer required, it can be closed with the function block FB_SocketClose. Several clients can establish a connection with the remote server at the same time. For each new client, a new socket is opened and a new connection handle is returned. The TwinCAT TCP/IP Connection Server automatically assigns a new IP port number for each client. The TLS parameters can be defined via the function blocks FB_TlsSocketAddCa, FB_TlsSocketAddCrl, FB_TlsSocketSetPsk and FB_TlsSocketSetCert. Programming samples for their use can be found in our samples.

Inputs

VAR_INPUT
    sSrvNetId   : T_AmsNetId:='';
    sRemoteHost : STRING(TCPADS_TLS_HOSTNAME_SIZE):='';
    nRemotePort : UDINT:=0;
    flags       : ST_TlsConnectFlags:=DEFAULT_TLSCONNECTFLAGS;
    bExecute    : BOOL;
    tTimeout    : TIME:=T#45s;(*!!!*)
END_VAR

Setting the maximum execution time of the function block Do not set the value "tTimeout" too low, as timeout periods of > 30 s can occur in case of a network interruption. If the value is too low, command execution would be interrupted prematurely, and ADS error code 1861 (timeout elapsed) would be returned instead of the Winsocket error WSAETIMEDOUT.

Inputs/outputs

VAR_IN_OUT
    hSocket : T_HSOCKET;
END_VAR

Outputs

VAR_OUTPUT
    bBusy  : BOOL;
    bError : BOOL;
    nErrId : UDINT;
END_VAR