eipReadAttr
Function Block - Ethernet/IP explicit messaging - read single attribute.
This function block sends an explicit message (UCMM) to an Ethernet/IP adapter, for reading a single CIP attribute.
The CIP instance number can be 16 bits [1...65535].
Inputs
|
Input |
Data type |
Description |
|
Snd |
BOOL |
A rising edge on this input start the exchange. The DONE output will signal the end of exchange. |
|
SrvIP |
STRING |
A rising edge on this input start the exchange. The DONE output will signal the end of exchange. |
|
Class |
UINT |
Class identifier of the CIP object. |
|
Inst |
UINT |
Instance identifier of the CIP object. |
|
Attr |
UINT |
Identifier of the CIP attribute. |
|
Data |
array of USINT |
Buffer where to store the received data. If the actual attribute length is greater than the size of this array, value will be truncated when read. |
Outputs
|
Output |
Data type |
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. |
|
RevSize |
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 |
|
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 extracting data from the read buffer.
Example
// used variables
// Inst_eipReadAttr : eipReadAttr ;
// bRead : BOOL ; (* request for READ *)
// DataRead : ARRAY [0 .. 15] OF USINT ; (* read data *)
// Server identification and CIP things
#define SRVIP '192.168.33.21'
#define CLASSID UINT#100
#define INSTID_READ UINT#1
#define ATTRID UINT#3
/////////////////////////////////////////////////////////////////////////////////////////
// requested READ command
if bRead then
Inst_eipReadAttr (bRead, SRVIP, CLASSID, INSTID_READ, ATTRID, DataRead);
end_if;
// READ answer here ?
if Inst_eipReadAttr.Done then
// check answer - if OK answered data is in DataRead array
if Inst_eipReadAttr.Err = 0 then
printf ('READ ok - size = %lu bytes',
any_to_dint (Inst_eipReadAttr.RcvSize));
else
printf ('READ Error %lu (UCMM Error %lu, %lu)',
any_to_dint (Inst_eipReadAttr.Err),
any_to_dint (Inst_eipReadAttr.EmErr),
any_to_dint (Inst_eipReadAttr.EmErrExt));
end_if;
// reset READ command and block input
Inst_eipReadAttr (false, SRVIP, CLASSID, INSTID_READ, ATTRID, DataRead);
bRead := false;
end_if;
eipReadAttr |
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IEC 61131-3 Automation platform > Programming - Reference guide > Driver specific function blocks > EthernetIP Scanner > eipReadAttr |
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