Omron SYSMAC CS1W-CLK11 Operation Manual page 217

Data Link I/O Response Time
Input
Input device
Input ON delay
X
(1)
The equation for maximum data link I/O response time is as follows:
Input ON delay
Cycle time of PC at node #1 × 2
Communications cycle time × 3
PC cycle time at node #7 × 3 (see note)
Output ON delay
Total (data link I/O response time)
Note If the total number of data link words is greater than the maximum number of
words that can be exchanged per data exchange, the maximum data link I/O
response time will be cycle time of PC at node #7 × 4.
In case of the CQM1H, however, the cycle time will be incremented by the
value obtained from dividing the total number of data link words by the maxi-
mum number of words (1,200 words) per time.
For example, if the total number of data link words is 5,000, the result will be
as shown below.
5,000/1,200 = 2.5 (approx. 3)
Cycle time of PC at node #7 × (3+3)
Noise may increase I/O delays.
Case 2
The following diagram illustrates the data flow that will produce the maximum
data link I/O response time when the cycle time of the PC at node #1 ≥ the
communications cycle time and the cycle time of the PC at node #7 < the
communications cycle time.
1 cycle
Program
X
(2)
Communications
cycle time
PC at node #7
Data link I/O response time
There are three points shown in the diagram above where processing is
delayed, increasing the data link I/O response time.
1.5 ms
15 ms × 2
9.9 ms × 3
20 ms × 3 (see note)
15 ms
136.2 ms
PC at node #1
Controller Link Unit
transmission processing
Data link transmission
Controller Link Unit
transmission processing
X
(3)
Program
1 cycle
Output device
Section 8-3
I/O refresh
Data exchange
Output ON
delay
Output
201