2 Motion Control Configuration and Principles
2-24
NJ/NX-series CPU Unit Motion Control Userās Manual (W507)
The PLC Function Module sends motion control commands to the MC Function Module when motion
control instructions are executed in the user program. The MC Function Module then performs motion
control processing based on those commands and sends the results of processing as commands to the
EtherCATās Servo Drive or other device.
This type of data exchange is updated as shown in the following processing period.
ļ¬ NX701 CPU Unit
⢠Primary period = Motion control 1 period = Process data communications cycle for EtherCAT
communications 1
⢠Task period of the priority-5 periodic task = Motion control 2 period = Process data communica-
tions cycle for EtherCAT communications 2
*1 If the sequence control period is primary period, the motion control period and the communications cycle are
primary period.
If the sequence control period is the task period of the priority-5 periodic task, the motion control period and
the communications cycle are the task period of the priority-5 periodic task.
2-4-3 Relationship between Process Data Communications Cycle and
Motion Control Period
Slaves
CPU Unit
Processing in slaveEtherCAT
Motion control processing
by MC Function Module
Execution of user
program in PLC
Function Module
Sequence control period
*1
Motion control period Communications cycle Data refresh
period in slave
(depends on the slave)