ECATReadSDO

 Function Block A function block groups an algorithm and a set of private data. It has inputs and outputs. - Reads a 32-bit word from I/O nodes using a CANopen SDO read command.

Inputs

Input	Data Type	Range	Unit	Default	Description
Execute	BOOL	0, 1	N/A	No default	On the rising edge A rising edge is the transition of a digital signal from low to high. It is also called positive edge of Execute, an SDO read command is issued. The function block only handles one SDO command at a time. If Execute is toggled quickly so that another rising edge occurs before the SDO command has completed, the function block does not issue a second SDO command.
Index	INT	No range	N/A	No default	The object directory index of the data to be read. For more information, see: Communication SDOs Manufacturer specific SDOs Profile specific SDOs To read/write an SDO object with an index greater than 16#7FFF (32767), the value must be entered in this form: any_to_int(index # in hex format). Example: any_to_int(16#8321).
SubIndex	SINT	No range	N/A	No default	The sub-index of the object directory variable to be read. For more information, see: Communication SDOs Manufacturer specific SDOs Profile specific SDOs To read/write an SDO object with an index greater than 16#7FFF (32767), the value must be entered in this form: any_to_int(index # in hex format). Example: any_to_int(16#8321).
Size	SINT	1 to 4	N/A	No default	The size (i.e., number of bytes) to write.
DeviceAddress	INT	No range	N/A	No default	The EtherCAT ***EtherCAT is an open, high-performance Ethernet-based fieldbus system. The development goal of EtherCAT was to apply Ethernet to automation applications which require short data update times (also called cycle times) with low communication jitter (for synchronization purposes) and low hardware costs address of the device from which data is written to. The first node usually has the value 1001. The second node usually has the value 1002. Alternately, use the members of the EtherCAT structure to specify a device's address to Create Variables.

Outputs

Output	Data Type	Range	Unit	Description
Done	BOOL	No range	N/A	Indicates whether this function block has completed without error.
Error	BOOL	No range	N/A	Indicates whether this function block has completed with error.
ErrorID	DINT	No range	N/A	The SDO call error result, if Error is TRUE. See EtherCAT Error Codes. Upon success, Error is set to 0 (zero).
Value	DINT	No range	N/A	The value of the object directory variable being read. Value is only set when an SDO read command has successfully completed.

Remarks

• 
  

• This function block uses and reserves the EtherCAT SDO Channel.
  The SDO Channel remains reserved until the done output is TRUE.
  This FB should be called at each cycle until the done output is TRUE.
  If it is not called at each cycle, the rest of SDO communication (e.g., the AKD GUI "Graphical User Interface" A GUI is a type of user interface which allows people to interact with a computer and computer-controlled devices Views) is blocked.
  Using this FB in SFC "Sequential Function Chart" It can be used to program processes that can be split into steps. The main components of SFC are: - Steps with associated actions - Transitions with associated logic conditions - Directed links between steps and transitions P0 or P1 steps is not recommended because these steps are executed only once.
  If this FB is used in P0 or P1, then it must be used in an SFC N step to ensure the FB completes.

• Is typically used to query the status of inputs.
• See the FAQ to set the update rate for SDO communication.
• See EtherCAT Function Blocks that Work with SDOs for information about function blocks which are used to work with drive or remote I/O parameters that are not supported by ML and MC function blocks.

State Diagram

Figure 6-76: ECATReadSDO State Diagram

EtherCAT Error Codes

Figure 6-77: ECATReadSDO

FBD Language Example

FFLD Language Example

IL Language Example

Not available.

ST Language Example

(* Read PL.KP on first AKD Drive on EtherCAT network *)
Inst_ECATReadSdo( TRUE, 16#3542, 0, 4, 1001 );
PositionProportionalGain := Inst_ECATReadSdo.Value;

(* Read the 4 byte data in SDO index 8321h (33569 decimal), sub-index 1 on the first AKD Drive
Inst_ECATReadSdo( TRUE, any_to_int(16#8321), 1, 4, 1001 );
ParamValue := Inst_ECATReadSdo.Value;

See Also

ECATWriteSDO