Omron CS1W-RPT01 Manuale Utente
264
Data Link I/O Response Time
Section 8-3
2.
Data exchange occurs just after the PLC at node #1 passes the token that
makes it the polling node, causing a delay of up to one communications cy-
cle time before the data is transferred in data link processing.
makes it the polling node, causing a delay of up to one communications cy-
cle time before the data is transferred in data link processing.
3.
At node #7, data from the previous data exchange is still being transferred,
causing a delay of up to one cycle before the input is read into the PLC.
causing a delay of up to one cycle before the input is read into the PLC.
4.
The data transferred in data link processing arrives at the PLC at node #7
after data exchange, so the data will not be read into the PLC until the next
data exchange, causing a delay of up to one peripheral servicing interval.
after data exchange, so the data will not be read into the PLC until the next
data exchange, causing a delay of up to one peripheral servicing interval.
Up to 3,700 words can be transferred in a single data exchange, so a delay
of another peripheral servicing interval will occur if more than 3,700 words
are being transferred.
of another peripheral servicing interval will occur if more than 3,700 words
are being transferred.
5.
The data is received after the PLC at node #7 has executed the instruction,
causing a delay of up to one cycle time.
causing a delay of up to one cycle 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:
is 10 ms. The equation for maximum data link I/O response time is as follows:
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
response time will be cycle time of PLC at node #7
×
3.
Noise may increase I/O delays.
Minimum Response Time
Input ON delay
1.5 ms
Cycle time of PLC at node #1
×
2
15 ms
×
2
Peripheral servicing interval of PLC at
node #1
node #1
10 ms
Communications cycle time
×
3
9.9 ms
×
3
Peripheral servicing interval of PLC at
node #7
node #7
×
2
10 ms
×
2
PLC cycle time at node #7
×
2 (See note.) 20 ms
×
2 (See note.)
Output ON delay
15 ms
Total (data link I/O response time)
146.2 ms
Input
Input device
Input ON delay
1 cycle
I/O refresh
PLC at node #1
PLC at node #7
Peripheral servicing interval
Peripheral servicing interval
Output device
Output
ON delay
ON delay
Data link I/O response time
Program
◆
◆
Program
Data link transmission
Data processing time
Data processing time