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Data Link I/O Response Time Section 8-3
CVM1 and CV-series PLCs
Under Asynchronous
Operation
When a CVM1 or CV-series CPU Unit is operating in asynchronous mode,
data exchange with the Controller Link Unit is executed as interrupt process-
ing during peripheral processing, regardless of the cycle time of PLC instruc-
tion execution. Data exchange timing is as follows:
More than one data exchange can be executed during a PLC cycle, depend-
ing on the data exchange timing. If interrupt processing for data exchange is
executed, the peripheral servicing interval will be lengthened by the time
required for the interrupt processing (see 8-3-2 Data Processing Time on
page 254).
CS/CJ-series PLCs, CVM1
and CV-series PLCs in
Synchronous Mode,
CQM1H-series PLCs, and
C200HX/HG/HE PLCs
When a CS/CJ-series, CQM1H-series, CVM1, or CV-series PLC is operating
in synchronous mode, a CQM1H-series, or a C200HX/HG/HE PLC is operat-
ing, data exchange with the Controller Link Unit is executed as processing
during peripheral processing for the PLC cycle. Data exchange timing is as
follows:
If processing for data exchange is executed, the PLC cycle time will be length-
ened by the time required for the interrupt processing (see 8-3-2 Data Pro-
cessing Time below).
8-3-2 Data Processing Time
The time required to process 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 PLC. If the number of data link words exceeds
the value shown in the table, data exchange will be executed as several sepa-
rate processes.
Instruction execution
PLC cycle time
Execution
I/O refreshing
PLC processing
Peripheral processing
Peripheral servicing interval
Basic processing
CPU Bus
Unit service
Programming
Device/Host Link
service
Interrupt processing
for data exchange
Execution Execution
I/O refreshing I/O refreshing
Interrupt processing
for data exchange
Interrupt processing
for data exchange
Basic
p
rocessin
g
CPU Bus
Unit service
Programming
Device/Host Link
service
CPU Bus
Unit service
Programming
Device/Host Link
service
Basic
p
rocessin
g
PLC cycle time
Execution
PLC processing
Basic processing
ExecutionI/O refreshing
Basic processing
Processing for
data exchange
Peripheral
service
CPU Unit Equation estimating data processing time
CS1-H, CJ1-H, CJ1M CPU Unit 0.1 ms + Number of transfer words × 0.7 µs
CS1, CJ1 CPU Unit 1.5 ms + Number of transfer words × 1 µs
CVM1-series CPU Unit 1.7 ms + Number of transfer words × 1 µs