CIA405.SDO_READ4 (FB)

Input:

NETWORK	USINT	see CIA405.CIA405BASE
ENABLE	BOOL	see CIA405.CIA405BASE
TIMEOUT	UDINT	see CIA405.CIA405BASE
DEVICE	CIA405.DEVICE	Addressed device; 0 means local device range: 0 … 127 initial: 0
CHANNEL	USINT	SDO channel number range: 1 … 128 initial: 1
INDEX	WORD	Object index range: 0000 … FFFF initial: 0
SUBINDEX	BYTE	Object subindex range: 00 … FF initial: 0

Output:

CONFIRM	BOOL	see CIA405.CIA405BASE
ERROR	CIA405.CANOPEN_ KERNEL_ERROR	see CIA405.CIA405BASE
DATA	ARRAY OF BYTE	Object data range: 00 00 00 00 … FF FF FF FF initial: 0 0 0 0
DATALENGTH	USINT	Length of valid data in bytes range: 0 … 4 initial: 0
ERRORINFO	CIA405.SDO_ERROR	SDO Abort code range: 0 … 2³²-1 initial: 0

插图 564: Request/Response diagram

The figure above shows the timing diagram for CIA405.SDO_READ4. After all data is provided to the inputs, ENABLE is set to TRUE (1). The SDO will be received, and when the CANopen software reports success to the function block, output CONFIRM will be changed to TRUE (2). The caller will see this and change ENABLE to FALSE (3), which in turn will cause output CONFIRM to change to FALSE (4).

With a rising edge on input ENABLE, the function block will sample the inputs and initiate the transmission of the SDO specified with DEVICE, INDEX and SUBINDEX. The value of DEVICE is limited to a range of 1 to 127. For access to the local object dictionary it is allowed to use the value 0 for DEVICE.
With TRUE on input ENABLE, the function block is allowed to continue execution. If a result is reported on the call by lower level CANopen software, outputs CONFIRM, DATA and DATALENGTH (in case of success) or ERROR and ERRORINFO (in case of failure) are set accordingly.
With a falling edge on input ENABLE the function block will terminate. If the transmission did not finish yet, it will be aborted if possible. Outputs CONFIRM and ERROR will both be set to FALSE respectively "no error".
With a FALSE on input ENABLE, the function block will return immediately and not take any action.
For behavior of ENABLE, CONFIRM and ERROR see chapter ⇘ “Control mechanism”.
For inputs NETWORK and TIMEOUT see chapter ⇘ Additional parameters.
The output DATA defined as ARRAY[1..4] OF BYTE contains the least significant data byte at the lowest array index. Example: the value 16#01020304 (hexadecimal) is assigned as ARRAY[1..4] OF BYTE := 04, 03, 02, 01