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The "itfAsyncProperty" must be passed during initialization. Otherwise the FB "ResolveHostname" is executed synchronously, which leads to an increased cycle time

CODESYS FAQ > TCP, ResloveHostname: Using the Interface "itfAsyncProperty" > NOK_AsyncProp.png

(Compare this also with the screeshot at the end of this article)

Create a "Standard project" and select CODESYS Control Win V3 as the device.
Define the target system by means of the Network scan.
Open the Library Manager and add the following libraries:
Net Base Services

Edit the PLC_PRG POU as follows:

Declaration

VAR
	fbAsyncProperty		: NBS.AsyncProperty := (tnTaskName := 'itfAsyncTask', usiTaskPrio := 75, udiTaskInterval := 1000);
    fbResolveHostname	: NBS.ResolveHostname := (itfAsyncProperty := fbAsyncProperty);
    xResolve			: BOOL;
    ipAddress			: NBS.IPv4Address;
    itfIpAddress		: NBS.IIPAddress := ipAddress;
END_VAR

Implementation

fbResolveHostname(xExecute:= xResolve, 
					udiTimeOut:= 10000000, //10 seconds
					sHostname:= 'www.codesys.com', 
					itfIPAddress:= itfIpAddress);

IF fbResolveHostname.xDone THEN
	xResolve := FALSE;
END_IF

Load the project to the controller and start it. Set The variable xResolve to TRUE.