FB_EcLogicalReadCmd

FB_EcLogicalReadCmd 1:

The master sends a logical EtherCAT read command (LRD) with the function block FB_EcLogicalReadCmd. In each slave, local address ranges (DPRAM) can be mapped to global logical address ranges. This command therefore addresses all EtherCAT slaves, which have mapping configured for the selected logical address range.

Inputs

VAR_INPUT
    sNetId   : T_AmsNetId; 
    logAddr  : UDINT; 
    len      : UDINT;
    pDstBuf  : PVOID;
    bExecute : BOOL;
    tTimeout : TIME := DEFAULT_ADS_TIMEOUT;
END_VAR

Name	Type	Description
sNetId	T_AmsNetId	String containing the AMS network ID of the EtherCAT master device. (Type: T_AmsNetId)
logAddr	UDINT	Logical address
len	UDINT	Number of bytes to be read
pDstBuf	PVOID	Address (pointer) to the receive buffer
bExecute	BOOL	The function block is activated by a positive edge at this input.
tTimeout	TIME	Maximum time allowed for the execution of the function block.

Outputs

VAR_OUTPUT
    bBusy  : BOOL;
    bError : BOOL;
    nErrId : UDINT;
    wkc    : UINT; 
END_VAR

Name	Type	Description
bBusy	BOOL	This output is set when the function block is activated, and remains set until a feedback is received.
bError	BOOL	This output is set after the bBusy output has been reset when an error occurs in the transmission of the command.
nErrId	UDINT	Supplies the ADS error code associated with the most recently executed command if the bError output is set.
wkc	UINT	The working counter is incremented by each EtherCAT slave that has processed this command successfully. If only one EtherCAT slave was addressed by this command, this value should therefore be 1.

Example of an implementation in ST:

PROGRAM Test_LogicalReadCmd
VAR
    fbReadCmd : FB_EcLogicalReadCmd;
    bExecute  : BOOL;
    value     : USINT;
    logAddr   : UDINT :=16#10000;
    sNetId    : T_AmsNetId:='192.168.1.5.3.1';
    wkc       : UINT;
    bError    : BOOL;
    nErrId    : UDINT;
END_VAR

fbReadCmd (sNetId:=sNetID, logAddr:=logAddr, LEN := SIZEOF(value), pDstBuf:=ADR(value), bExecute:=bExecute);
wkc := fbReadCmd.wkc;
bError:= fbReadCmd.bError;
nErrId:= fbReadCmd.nErrId;

Requirements

Development environment	Target platform	PLC libraries to include
TwinCAT v3.1.0	PC or CX (x86, x64, ARM)	Tc2_EtherCAT