Omron NX102 series User Manual

3-5
3 EtherCAT Communications
NJ/NX-series CPU Unit Built-in EtherCAT Port User’s Manual (W505)
3-1 EtherCAT Communications Types and Settings
3
3-1-2 Types of Communications
The following two methods are used to exchange data between master and slaves in EtherCAT com-
munications.
PDO communications is used for constant data exchange between the master and slaves. It is called
process data communications. PDO data (i.e., I/O data that is mapped to PDOs) that is allocated in
advance is input and output periodically each EtherCAT process data communications cycle (i.e., the
task period of primary periodic task or priority-5 periodic task).
It is accessed from the NJ/NX-series CPU Unit in the following ways.
• With device variables for EtherCAT slave I/O
• With Axis Variables for Servo Drive and encoder input slaves to which an axis is allocated
Additional Information
You can use the priority-5 periodic task only with NX701 CPU Units.
3-1-2 Types of Communications
Communication
type
Name of communication
type
Timing of processing Type of data
Cyclic
communications
Process data
communications
(PDO communications)
Constant
(process data communications cycle)
PDO data
Message
communications
SDO communications When required. SDO data
Process Data Communications (PDO Communications)
EC_CoESDORead/
EC_CoESDOWrite
IN
OUT
EtherCAT
IN
OUT
SDO data
PDO
data
SDO data
PDO
data
SDO communications:
When required
(from instruction or
Sysmac Studio)
Constant data exchange
(process data communications cycle = each period of primary periodic task)
Process data communications:
* Device variables for EtherCAT slaves
Axis Variables only for Servo Drive and encoder input slaves to which axes are allocated
Message communications (for SDO data)
Device
variables and
Axis Variables*
Cyclic communications (for PDO data)
EtherCAT communications
CPU Unit

Omron NX102 series Specifications

General

Brand	Omron
Model	NX102 series
Category	Controller
Language	English