FB_MDP_ReadIndex

The function block enables an element of the IPC diagnosis data to be queried. This can be part of the configuration area as well as the device area.

VAR_INPUT

VAR_INPUT
    bExecute        : BOOL;             (* Function block execution is triggered by a rising edge at this input.*)
    nIndex          : WORD;
    nSubIndex       : BYTE;
    pDstBuf         : POINTER TO BYTE;          (* Contains the address of the buffer for the received data. *)
    cbDstBufLen     : UDINT;            (* Contains the max. number of bytes to be received. *)
    tTimeout        : TIME := DEFAULT_ADS_TIMEOUT;  (* States the time before the function is cancelled. *)
    sAmsNetId       : T_AmsNetId;           (* keep empty '' for the local device *)
END_VAR

bExecute	The function block is called by a rising edge on the input bExecute, if the block is not already active.
nIndex	The first part of the addressing belonging to the selected element is specified at this input.
nSubIndex	The second part of the addressing belonging to the selected element is specified at this input.
pDstBuf	The memory address of the data buffer is specified at this input. The received data are stored there if the query is successful.
cbDstBufLen	The length of the data buffer in bytes is specified at this input.
tTimeout	Specifies a maximum length of time for the execution of the function block.
sAmsNetId	For local access don't specify this input or allocate an empty string. For remote access to another computer specify its AMS Net Id.

VAR_OUTPUT

VAR_OUTPUT
    bBusy       : BOOL;
    bError      : BOOL;
    nErrId      : UDINT;
    nCount      : UDINT;
END_VAR

bBusy	This output is TRUE as long as the function block is active.
bError	Becomes TRUE as soon as an error situation occurs.
nErrID	Returns an error code if the bError output is set.
nCount	This output indicates the number of bytes read.

Requirements

Development environment	Target system type	PLC libraries to include
TwinCAT v2.11.0 Build >= 1541	PC or CX (x86, ARM)	TcMDP.Lib [version 1.4.0 or higher]