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I/O Response Time in Tag Data Links Section 10-3
10-3 I/O Response Time in Tag Data Links
Note This section describes the data processing time for an EtherNet/IP Unit or a
built-in EtherNet/IP port on a CJ2H-CPU6@-EIP CPU Unit. The data process-
ing time for a built-in EtherNet/IP port on the CJ2M-CPU3@ CPU Unit is differ-
ent. For details, refer to 10-4 Tag Data Link Performance for CJ2M Built-in
EtherNet/IP Ports.
10-3-1 Timing of Data Transmissions
The following diagram shows the timing of tag data link transmissions
between the EtherNet/IP Unit or CJ2H built-in port and the CPU Unit.
The data transmission is processed during the I/O refresh period. Send data
is processed with transmission at regular intervals, and received data is pro-
cessed together with the send data when new data has been received from
other nodes. The following diagram shows the timing of data transmissions.
If there is an interrupt for data transmission processing, the CPU Unit’s cycle
time is extended by that interrupt processing time. Refer to 10-3-2 EtherNet/IP
Unit or CJ2H Built-in Port Data Processing Time for details.
10-3-2 EtherNet/IP Unit or CJ2H Built-in Port Data Processing Time
The following formula approximates the time required for the EtherNet/IP Unit
or CJ2H built-in port to process data transmissions with the CPU Unit (i.e., the
data processing time).
CPU Unit processing
Basic
pro-
cesses
Program
execution
I/O refreshing
Peripheral
servicing
Data exchange processing
Basic
pro-
cesses
Data received
EtherNet/IP
Unit processing
EtherNet/IP Unit data
processing time
(Refer to 10-3-2.)
CPU Unit’s c
y
cle time
Approximation of the data processing time for an
EtherNet/IP Unit or CJ2H Built-in Port
(0.0008 × Number of data transmission words) + 1.0 ms