BECKHOFF FC5101 - Manual (Page 57)

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57
IF SDO_READ.ReadDataAvailable THEN
ReadStart := FALSE;
ReadError := SDO_READ.Error;
ReadData := SDO_READ.ReadData;
END_IF
The SDO_READ function block that has been called in turn calls the ADSREAD function a number of times. It
looks like this (starting with the variable declaration):
FUNCTION_BLOCK SDO_READ
VAR_INPUT
ADSNetID:STRING(23); (* The AMSNetID addresses the FC5101 card. Can be empty if
only one local single channel card is present*)
PortNr:WORD; (* This Port No. addresses the CANopen Node (see System
Manager) *)
CO_Index:DWORD; (* This is the Index of the CANopen Object Dictionary En-
try*)
CO_SubIndex:DWORD; (* This is the Sub-Index of the CANopen Object Dictionary
Entry*)
DataLength:DWORD; (* This is the Length of the CANopen Object Dictionary En-
try*)
StartReading:BOOL; (* only reset to FALSE after ReadDataAvailable=TRUE*)
END_VAR
VAR_OUTPUT
ReadData:ARRAY[0..255] OF BYTE;
ReadDataAvailable:BOOL;
Error:DWORD;
END_VAR
VAR
state:BYTE := 0;
ADSREAD:ADSREAD;
END_VAR
CASE state OF
0:
IF StartReading THEN
ReadDataAvailable := FALSE;
Error := 0;
ADSRead(
NETID:= ADSNetID,
PORT:= PortNr,
IDXGRP:= CO_Index,
IDXOFFS:= CO_SubIndex,
LEN:= DataLength,
DESTADDR:= ADR(ReadData),
READ:= TRUE,
TMOUT := T#1s
);
IF ADSRead.err THEN
state := 2;
ReadDataAvailable := TRUE;
Error := ADSRead.ErrId;
ELSE
state := 1;
END_IF
ELSE
ADSRead(
NETID:= ADSNetID,
PORT:= PortNr,
IDXGRP:= CO_Index,
IDXOFFS:= CO_SubIndex,
LEN:= DataLength,
DESTADDR:= ADR(ReadData),
READ:= FALSE,
TMOUT := T#1s
);
END_IF