Tag Data Link I/O Response Time - Omron CJ1W-EIP21 - 10-2010 Operation Manual

Tag Data Link Performance for CJ2M Built-in EtherNet/IP Ports

10-4-2 Tag Data Link I/O Response Time

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For example, node 1 establishes 16 send connections and 16 receive connec-
tions to the other 16 nodes, for a total of 32 connections. The data size per
connection is 20 words for the send area to the other nodes and 20 words
each of the receive areas from the other nodes.
If the same RPI is set for all connections, 12 ms is the lowest setting that can
be used.
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Calculation Example
(1,000 ÷ 12 [ms] (RPI) + 1,000 ÷ 100 [ms] (heartbeat transmission period)) ×
32 (connections) = 2,987 pps < 3,000 pps
Send connections = 16
(20 words × 16 = 320 words)
Node 2
Node 1
Receive 20 words
Send 20 words
Receive 20 words
Send 20 words
Receive 20 words
Receive 20 words
Receive 20 words
Receive 20 words
Receive 20 words
Receive 20 words
With tag data links, if the data in the data link area for a node changes due to
an input to that node, a certain amount of time is required for the data in data
link area at another node to be updated and output.
The I/O response time for tag data links can be calculated for a CJ2M built-in
port in the same was as it can for a CJ2H built-in port (refer to 10-3-4 Tag
Data Link I/O Response Time Calculation Example). Here, formulas to calcu-
late guideline I/O response times are provided. (Tag data link delays are
ignored because the data link size handled by the built-in CJ2M port is small.)
Maximum I/O Response Time
Input ON delay + Cycle time of sending PLC × 2 + RPI + Cycle time of receiv-
ing PLC × 2 + Output ON delay
Minimum I/O Response Time
Input ON delay + Cycle time of sending PLC + Cycle time of receiving PLC +
Output ON delay
Node 3
Receive 20 words
Receive 20 words
Send 20 words
Receive 20 words
Receive 20 words
Receive connections = 16
(20 words × 16 = 320 words)
Section 10-4
*All nodes use CJ2M built-in ports.
Node 17
Node 16
Receive 20 words Receive 20 words
Receive 20 words
Receive 20 words
Receive 20 words Receive 20 words
Send 20 words
Receive 20 words
Send 20 words
Receive 20 words