Omron C200HW-CLK21 Operation Manual page 286

Data Link I/O Response Time
CVM1 and CV-series PLCs Under Asynchronous Operation
Maximum Response Time
Input
Input ON delay
(1)
Program
1,2,3...
The equation for minimum data link I/O response time is as follows:
Input ON delay
Cycle time of PLC at node #1
PLC cycle time at node #7 (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 PLC at node #7
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 PLC at node #7
Noise may increase I/O delays.
Input device
1 cycle
(2)
Controller Link Unit transmission processing
Communications
cycle time
PLC at node #7
Data link I/O response time
There are five points shown in the diagram above where processing is
delayed, increasing the data link I/O response time.
1. The input arrives in the PLC just after I/O refreshing, causing a delay of up
to one cycle before the input is read into the PLC.
---
15 ms
20 ms (See note.)
---
35 ms
(1+3)
PLC at node #1
Peripheral servicing interval
Data link transmission
(3)
Controller Link Unit transmission processing
Previous communica-
tions cycle data
(4)
1 cycle
Output device
Section 8-3
3.
I/O refresh
Peripheral servicing interval
Program
Output ON
delay
Output
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