Omron SYSMAC CS1W-RPT01 Operation Manual page 288

Data Link I/O Response Time
Minimum Response Time
Assume that the peripheral servicing interval of the PLCs at nodes #1 and #7
is 10 ms. The equation for maximum data link I/O response time is as follows:
Input ON delay
Cycle time of PLC at node #1 × 2
Peripheral servicing interval of PLC at
node #1
Communications cycle time × 3
Peripheral servicing interval of PLC at
node #7 × 2
PLC cycle time at node #7 × 2 (See note.) 20 ms × 2 (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 × 3.
Noise may increase I/O delays.
Input
Input ON delay
Data link I/O response time
In this case, the data processing time required for data exchange and the data
transmission time are not negligible and need to be included in the calcula-
tion. Each time can be determined as follows.
Data Processing Time (see page 258.)
0.0025 × (8 + 16) × 8 + 4.7 = 5.18 ≅ 5.2 ms
Data Transmission Time
Data transmission time varies with the baud rate.
Baud rate
Number of data link words × 0.008 ms
2 Mbps
Number of data link words × 0.016 ms
1 Mbps
Number of data link words × 0.032 ms
500 Kbps
In this example, the number of data link words is (8 + 16) × 8 = 192, so the
data transmission time can be determined as follows:
0.008 × (8 + 16) × 8 = 1.536 ≅ 1.5 ms
1.5 ms
15 ms × 2
10 ms
9.9 ms × 3
10 ms × 2
15 ms
146.2 ms
Input device
1 cycle
◆ Program
Peripheral servicing interval
Data processing time
Data link transmission
Data processing time
Program ◆
Output
ON delay
Data transmission time
Section 8-3
I/O refresh
PLC at node #1
Peripheral servicing interval
PLC at node #7
Output device
263