eipWriteAttr

Function Block - Ethernet/IP explicit messaging - write single attribute.

This function block sends an explicit message (UCMM) to an Ethernet/IP adapter, for writing a single CIP attribute.

The CIP instance number can be 16 bits [1...65535].

Inputs

Parameter	Description	Description
Snd	BOOL	A rising edge on this input start the exchange. The DONE output will signal the end of exchange.
SrvIP	STRING	IP address of the server (adapter) such as configured in the "Ethernet/IP Scanner" configuration.
Class	UINT	Class identifier of the CIP object.
Inst	UINT	Instance identifier of the CIP object.
Attr	UINT	Identifier of the CIP attribute.
Size	UINT	Number of bytes to write. Cannot exceed 450 bytes.
Data	array of USINT	Buffer containing the data to write.

Outputs

Parameter	Description	Description
Done	BOOL	This output is TRUE during one cycle when the exchange is finished, whatever the exchange succeeded or failed. Warning, this output can be TRUE just after the call to block when starting a new exchange in case of invalid parameters.
RcvSize	UINT	Actual size of the CIP attribute answered by the server. If this size if greater than the size of the DATA input array, it indicates that the value was truncated.
Err	UINT	Main error report. Can be one of the following values: 0 = no error 1 = invalid input arguments 2 = system is busy (see remarks) 3 = timeout waiting for the answer (the timeout value is 3 seconds 4 = UCMM error was returned by the server others = internal errors (reserved for technical support)
EmErr	UINT	in case of a UCMM error, this is the CIP general status error code.
EmErrExt	UINT	in case of a UCMM error, this is the CIP extended status error code.

Remarks

The servers (adapters) accessed by this block must be configured in the "Ethernet/IP Scanner" fieldbus configuration.

Only one explicit message (read or write) can be sent at one time to the same server. If another message is pending then you will get the error report 3 (busy) after calling the block to start a new exchange.

Consider SERIALIZEIN and SERIALIZEOUT functions for storing data to the write buffer.

Example

// used variables

// Inst_eipWriteAttr : eipWriteAttr ;

// bWrite : BOOL ; (* request for WRITE *)

// DataWrite : ARRAY [0 .. 15] OF USINT; (* written data *)

// uiSizeWrite : UINT := UINT#16 ; (* number of bytes to read *)

// Server identification and CIP things

#define SRVIP '192.168.33.21'

#define CLASSID UINT#100

#define INSTID_WRITE UINT#2

#define ATTRID UINT#3

/////////////////////////////////////////////////////////////////////////////////////////

// requested WRITE command

if bWrite then

Inst_eipWriteAttr (bWrite, SRVIP, CLASSID, INSTID_WRITE, ATTRID,

uiSizeWrite, DataWrite);

end_if;

// WRITE answer here ?

if Inst_eipWriteAttr.Done then

// check answer

if Inst_eipWriteAttr.Err = 0 then

printf ('WRITE ok');

else

printf ('WRITE Error %lu - (UCMM Error %lu, %lu)',

any_to_dint (Inst_eipWriteAttr.Err),

any_to_dint (Inst_eipWriteAttr.EmErr),

any_to_dint (Inst_eipWriteAttr.EmErrExt));

end_if;

// reset WRITE command and block input

Inst_eipWriteAttr (false, SRVIP, CLASSID, INSTID_WRITE, ATTRID,

uiSizeWrite, DataWrite);

bWrite := false;

end_if;

eipWriteAttr

IEC 61131-3 Automation platform > Programming - Reference guide > Driver specific function blocks > EthernetIP Scanner > eipWriteAttr

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