FB_SocketConnect
Using the function block FB_SocketConnect, a local client can establish a new TCP/IP connection to a remote server via the TwinCAT TCP/IP Connection Server. 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.
VAR_INPUT
VAR_INPUT
sSrvNetId : T_AmsNetId := '';
sRemoteHost : STRING(15);
nRemotePort : UDINT;
bExecute : BOOL;
tTimeout : TIME := T#45s;(*!!!*)
END_VAR
sSrvNetId: string containing the network address of the TwinCAT TCP/IP Connection Server. For the local computer (default) an empty string may be specified.
sRemoteHost: IP address (Ipv4) of the remote server as a string (e.g. '172.33.5.1'). An empty string can be entered on the local computer for a server.
nRemotePort: IP port number of the remote server (e.g. 200).
bExecute: the function block is enabled via a positive edge at this input.
tTimeout: maximum time that may not be exceeded when the function block is executed.
 | The tTimeout value should not be set too low, since timeout periods of > 30 s may occur in the event 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. |
VAR_OUTPUT
VAR_OUTPUT
bBusy : BOOL;
bError : BOOL;
nErrId : UDINT;
hSocket : T_HSOCKET;
END_VAR
bBusy: When the function block is activated this output is set. It remains set until and acknowledgement is received.
bError: If an error should occur during the transfer of the command, then this output is set once the bBusy output was reset.
nErrId : If the bError output is set, this parameter returns the TwinCAT TCP/IP Connection Server error number.
hSocket: TCP/IP connection handle for the newly opened local client socket.
Requirements
Development environment | Target system type | PLC libraries to be linked |
|---|---|---|
TwinCAT version 2.8.0 or higher | PC or CX (x86) | TcpIp.Lib ( Standard.Lib; TcBase.Lib; TcSystem.Lib are included automatically ) |
TwinCAT v2.10.0 Build >= 1301 | CX (ARM) |