Equipments (Devices) > SCA06 > Ladder > Communication Network > CANopen > CO

Block that performs a writing of data via SDO from a remote slave in CANopen network.

Ladder Representation

CO_SDOWRITE_block

Block Structure

Variable Type	Name	Data Type	Description
VAR_INPUT	Execute	BOOL	Block enabling
	NodeID#	BYTE	Slave address
	Index#	WORD	Index of the object to be accessed in slave
	SubIndex#	BYTE	Sub-index of the object
	Size#	BYTE	Size of data accessed, in bytes
	Timeout#	WORD	Maximum waiting time for arrival of data, from the beginning of the request [ms]
	Value	BYTE USINT	Variable that has the data to be written
VAR_OUTPUT	Done	BOOL	Output enabling
	Active	BOOL	Awaiting response flag
	Busy	BOOL	Flag of the SDO client is busy with another request
	Error	BOOL	Error in the execution flag
	ErrorID	BYTE USINT	Identifier of the occurred error
VAR	CO_SDOWRITE_INST_0	CO_SDOWRITE	Instance of access to block structure

Operation

When this block detects a leading edge on Execute it checks whether the SDO client in the specified NodeID # address is free to send data (Busy variable at FALSE level). If so, it sends the writing request to the object of Size# size located in Index# and SubIndex# and sets the Active output, resetting it when receiving the response from the slave. If the slave is not free, the block waits Busy go to FALSE level to resubmit the request.

NOTE!

If Execute goes to FALSE level and Busy is still at TRUE level, the request is canceled.

NOTE!

Value is an array of size equal to Size#. It is important to check this compatibility not to generate errors in the block.

NOTE!

It is only possible to read one object (BYTE, WORD, DWORD) per block. It is not possible to read an array of objects.

When Execute has FALSE value, Done remains FALSE. The Done output is only activated when the block finishes executing successfully, remaining at TRUE level until Execute receives FALSE.

If there is any error in the execution, the Error output is enabled and ErrorID displays an error code according to the table below.

Code	Description
0	Executed successfully
1	Card cannot execute the function
2	Timeout in slave response
3	Slave returned error

Block Flowchart

CO_SDOWRITE_flowchart

Example in Ladder

CO_SDOWRITE_example01

The example above requests writing of the data size VALUE, located in INDEX - SUBINDEX, of the NODEID device. The block ends successfully, Done output is activated.

Example in ST

The example below displays the instructions for applying the example above in the ST language.

VAR

ERROR : BOOL;

INDEX, TIMEOUT : WORD;

NODEID, SUBINDEX : BYTE;

VALUE : UDINT;

CO_SDOWRITE_INST_0 : FB_CO_SDOWrite;

END_VAR

CO_SDOWRITE_INST_0.Execute := DI1;

CO_SDOWRITE_INST_0(

NodeId:=NODEID,

Index:=INDEX,

SubIndex:=SUBINDEX,

Size:=4,

Timeout:=TIMEOUT,

Value:=VALUE);

ERROR := CO_SDOWRITE_INST_0.Error;

DO1 := CO_SDOWRITE_INST_0.Done;