Omron CVM1-CLK21, Operation Manual

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Data Link I/O Response Time Section 8-3
CS/CJ-series PCs, CVM1
and CV-series PCs in
Synchronous Mode,
CQM1H-series PCs, and
C200HX/HG/HE PCs When a CS/CJ-series, CQM1H-series, CVM1, or CV-series PC is operating in
synchronous mode, a CQM1H-series, or a C200HX/HG/HE PC is operating,
data exchange with the Controller Link Unit is executed as interrupt process-
ing during peripheral processing for the PC cycle. Data exchange timing is as
follows:
If interrupt processing for data exchange is executed, the PC cycle time will be
lengthened by the time required for the interrupt processing (see 8-3-2 Data
Processing Time below).
8-3-2 Data Processing Time
The time required for interrupt processing for data exchange (data processing
time) can be roughly estimated as shown in the following table.
The number of words processed in a single data exchange is shown in the fol-
lowing table for each series of PC. If the number of data link words exceeds
the value shown in the table, data exchange will be executed as several sepa-
rate processes.
Note 1. Use the above equations only if only one Controller Link Unit is mounted
on the PC. If other CPU Bus Units are mounted on the PC, obtain the re-
fresh times for each CPU Bus Unit and add to the above equations.
2. The execution of some items takes precedence over data link area refresh-
ing. For example, data link area refreshing will not take place during exe-
cution of the SEND(192), RECV(193), or FAL(006) instruction.
8-3-3 Calculation Example
The data links of the Controller Link Unit require a slight time delay from the
time the data link area of one node is changed until this change is reflected in
the data link area at another node. This time delay is called the data link I/O
PC cycle time
Execution
PC processing
Basic processing
Interrupt processing
for data exchange
Execution
I/O refreshing Basic processing
CPU Bus
Unit service
Programming
Device/Host Link
service
Data link scale Equation for estimating data processing time
Data link is established for both areas 1 and 2 0.001
×
Total number of data link words + 1.7 (ms)
Data link is established for only area 1 or area 2 0.001
×
Total number of data link words + 1.4 (ms)
PCs Words per data exchange
CS/CJ-series PCs Approx. 7,800 words
CVM1 and CV-series PCs Approx. 3,700 words
C200HX/HG/HE PCs Approx. 4,000 words
CQM1H-series PCs Approx. 1,200 words