Omron NX-EC0112, Руководство пользователя

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5 I/O Refreshing Methods
5 - 2 NX-series Position Interface Units User’s Manual (W524)
5-1 I/O Refreshing for Slave Terminals
This section first describes I/O refreshing for NX-series Slave Terminals.
It then describes operation when the built-in EtherCAT port on the NJ/NX-series CPU Unit is used for
communications with an EtherCAT Slave Terminal.
The CPU Unit performs I/O refreshing cyclically with the Slave Terminals through the Communications
Master Unit and the Communications Coupler Unit.
The following four cycles affect operation of the I/O refreshing between the CPU Unit and the NX Units
in an Slave Terminal:
(a) CPU Unit cycle time
(b) Host network communications cycle
(c) Refresh cycle of the NX bus
(d) Refresh cycle of each NX Unit
The cycle time of the CPU Unit, the communications cycle of the host network, and the NX bus I/O
refresh cycle are determined by the model of the CPU Unit and the type of communications.
The operation of I/O refreshing is as follows when the built-in EtherCAT port on the NX-series CPU Unit
is used for communications with an EtherCAT Slave Terminal.
• The (b) process data communications cycle and (c) refresh cycle of the NX bus in the above figure
are automatically synchronized with the (a) task period of the primary periodic task or priority-5 peri-
odic task in the CPU Unit if the distributed clock is enabled in the EtherCAT Coupler Unit.
• The (d) refresh cycles of the NX Units depend on the I/O refreshing methods, which are described
later.
I/O Refreshing from the CPU Unit to the Slave Terminals
NX-series CPU Units and I/O Refresh Operation
CPU Unit
Data exchange between user
program and I/O Units
Slave Terminal
NX Unit NX Unit NX Unit
Other communications slave
Communications
path
(a)
(b)
(d) (d) (d)
(c)
Commu-
nications
Master
Unit
Communi-
cations
Coupler
Unit