Omron CJ1W-ECT21 Operation Manual page 104

4 EtherCAT Communications
Assigning PDOs to EtherCAT Slave Units
When assigning PDOs to the EtherCAT Slave Unit, refer to the IN and OUT data area size that have
been configured for the EtherCAT Slave Unit.
Assign PDOs of the same size as the setting value. PDOs are not assigned by default to an EtherCAT
Slave Unit. An example is shown in the table below.
I/O communication area reference table
Name
OUT data area size
IN data area size
Refer to 3-3 Device Variables for CJ-series Unit (I/O Communication Area Setting) on page 3-18 for the
I/O Communication Area Reference Table.
Refer to 4-4-2 PDO Mappings on page 4-5 for PDO Mapping of the EtherCAT Slave Unit.
Precautions for Correct Use
The IN and OUT data area size allocation for the EtherCAT Slave Unit must be the same size
as the PDO mapping for the EtherCAT master. Refer to 3-3 Device Variables for CJ-series Unit
(I/O Communication Area Setting) on page 3-18 for more information. If the sizes do not match,
an error will occur.
4 - 8
Name of device variable
for CJ-series Unit
*_RefOutAreaSize
*_RefInAreaSize
CJ-series EtherCAT Slave Units Operation Manual for NJ-series CPU Unit (W542)
Value
100 (100 bytes) 258th receive PDO Mapping
50 (50 bytes) 257th transmit PDO Mapping
PDO assignment