ClientTCP (FB)¶

FUNCTION_BLOCK ClientTCP EXTENDS Client

MODBUS TCP client (master).

Please note: some input variables related to connection configuration are read when rising edge on xConnect occurs. To change connection configuration the application needs to - disconnect (xConnect := FALSE and execute the FB) - modify the related input variables - connect (xConnect := TRUE and execute the FB)

The Client provides some statistics of sent request messages and received valid reply messages. Invalid messages are dropped at the communication level, so doesnt appear in the statistics. To analyse situations where invalid reply messages might occur, you can use udiLogOptions with LoggingOptions.WarnOnReceivedInvalidFrames.

Please visit https://forge.codesys.com/prj/codesys-example/modbus/home to find examples.

InOut:

Scope	Name	Type	Initial	Comment	Inherited from
Input	xConnect	BOOL	FALSE	Connect to server (slave).	Client
Output	xConnected	BOOL		Client (master) is connected to server (slave).	Client
	xError	BOOL		Error	Client
	eErrorID	Error		Error status	Client
	udiNumMsgSent	UDINT		Number of request messages send since connect.	Client
	udiNumMsgReply	UDINT		Number of reply messages received since connect.	Client
	udiNumMsgExcReply	UDINT		Number of exception reply messages received since connect.	Client
	udiNumMsgExcReplyIllFct	UDINT		Number of exception reply messages received since connect, signaling illegal function.	Client
	udiNumMsgExcReplyIllDataAdr	UDINT		Number of exception reply messages received since connect, signaling illegal data address.	Client
	udiNumReplyTimeouts	UDINT		Number of reply timeouts since connect.	Client
	udiNumReqNotProcessed	UDINT		Number of requests not processed in time (“request starvation”) since connect.	Client
	udiNumReqParamError	UDINT		Number of requests started with parameter error, for example “Read Coils” -> “Quantity of coils” = 0.	Client
	udiLastTransactionTime	UDINT		Transaction time in ms - time difference between request message send und reply message received.	Client
Input	aIPaddr	ARRAY [0..3] OF BYTE	[255, 255, 255, 255]	ETH server (slave) address, only read when rising edge on xConnect occurs.
	uiPort	UINT	502	ETH server (slave) port, only read when rising edge on xConnect occurs.
	tConnnectTimeOut	TIME	TIME#1s0ms	Connect timeout (in milliseconds), only read when rising edge on xConnect occurs.
	udiLogOptions	UDINT	LoggingOptions.ClientConnectDisconnect	Logging options.