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Opens a TCP network connection with the address and remote port or service name.

Use the TCP Close Connection function to close the connection.

Details  Examples

	address is the address with which you want to establish a connection. This address can be in IP dot notation or it can be a hostname. If you do not specify an address, LabVIEW establishes a connection to the local computer.
	remote port or service name can accept a numeric or a string input. remote port or service name is the port or name of the service with which you want to establish a connection. If you specify a service name, LabVIEW queries the NI Service Locator for the port number that the server registered.
	timeout ms is the period of time in milliseconds to wait before the function completes and returns an error. The default value is 60,000 ms or 1 minute. A value of –1 indicates to wait indefinitely.
	error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node. status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE. code is the error or warning code. The default is 0. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source specifies the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
	local port is the local connection port. Some servers only allow connections to clients that use port numbers within a specific range that is dependent on the server. If the value is 0, the operating system selects an unused port.
	connection ID is a network connection refnum that uniquely identifies the TCP connection. Use this value to refer to this connection in subsequent VI calls.
	error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error. status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred. code is the error or warning code. If status is TRUE, code is a nonzero error code. If status is FALSE, code is 0 or a warning code. source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.

TCP Open Connection Details

When wiring an unused IP address, you may receive an error stating the network operation exceeded the user-specified or system time limit. This error occurs before the default timeout of 60000 ms has occurred. To correct this error, wire an IP address that is running and listening on the port you are trying to use.

Examples

Refer to the following VIs for examples of using the TCP Open Connection function:

• TCP Communicator - Active VI: labview\examples\comm\TCP.llb
• Simple Data Client VI: labview\examples\comm\TCP.llb
• Named Service TCP Client VI: labview\examples\comm\TCP.llb