Omron CVM1 Series, Operation Manual

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PC Link System I/O Response Time Appendix C
Maximum I/O Response Time (in Synchronous Mode)
Maximum I/O response time = Input ON delay + (Cycle time of PLC #0
×
2) + (PC Link cycle time
×
2) + Poll-
ing sequence processing time + (Cycle time of PLC #7
×
(n + 1)) + Output ON
delay
• Example Calculation
If the PLCs are CVM1/CV-series PLCs, the multiplier (n) is 2.
Maximum I/O response time = 1.5 + (20
×
2) + (32.4
×
2) + 120 + (50
×
3) + 15 = 386.5 ms
Note (1) The I/O response time may be extended by environmental factors such as noise.
(2) Differences in I/O response times among different PLC models:
The PC Link Unit’s I/O response time is different in C1000H/C2000H PLCs and CVM1/CV-series
PLCs. When a CVM1/CV-series CPU Unit is operating in synchronous mode, it one PLC execution
cycle longer to read data from the PC Link, in comparison with a C1000H/C2000H PLC.
I/O response time
Node 0
(PLC #0)
PC Link transmission
Input
Processing
in PLC
PC Link buffer
Node 7
(PLC #7)
Output
Processing
in PLC
PC Link buffer
Max. transmission time
Instruction
execution
Cycle
time
Peripheral processing
PC Link
cycle time
Cycle
time
Instruction
execution
Solicitation
sequence
processing
PLC model n (multiplier)
CVM1/CV Series 2
C1000H/C2000H 1
C2000 3
Input ON delay 1.5 ms
Output ON delay 15 ms
Cycle time of PLC #0 20 ms
Cycle time of PLC #7 50 ms
PC Link Cycle Time 2.8
×
8 Units + 10 = 32.4 ms
Polling sequence processing time 15 ms
×
(16 Units
−
8 Units) = 120 ms