Omron CVM1-CLK21, Руководство по эксплуатации

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Data Link I/O Response Time Section 8-3
There are four points shown in the diagram above where processing is
delayed, increasing the data link I/O response time.
1,2,3... 1. The input arrives in the PC just after I/O refreshing, causing a delay of up
to one cycle before the input is read into the PC.
2. At point A, data from the previous exchange is still being transferred, so
new data cannot be exchanged, causing a delay of one communications
cycle time. Furthermore, the data exchange then occurs just after the PC
at node #1 passes the token for the polling node, causing another delay of
one communications cycle 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 PC.
4. The data transferred in data link processing arrives at the PC at node #7
after data exchange, so the data will not be read into the PC until the next
data exchange, causing a delay of up to one cycle.
The maximum number of words that can be exchanged in a single data ex-
change is approx. 7,800 words for CS/CJ-series PCs, approx. 3,700 words
for CVM1 and CV-series PCs, approx. 4,000 for C200HX/HG/HE PCs, and
approx. 1,200 words for CQM1H-series PCs.
The equation for maximum data link I/O response time is as follows:
Input device
Program
Program
Input
Input ON delay
1 cycle
Output
Output device
Output ON delay
1 cycle
Communications
cycle time
Data link transmission
Controller Link Unit
transmission processing
PC at node #7
(1)
I/O refresh
Data exchange
Controller Link Unit
transmission processing
PC at node #1
Previous communications
cycle data
Data link I/O response time
X
X
X
(2)
(3)
(4)
A
X
Input ON delay 1.5 ms
Cycle time of PC at node #1
×
2 8 ms
×
2
Communications cycle time
×
3 9.9 ms
×
3
PC cycle time at node #7
×
3 (see note) 20 ms
×
3 (see note)
Output ON delay 15 ms
Total (data link I/O response time) 122.2 ms