Omron SYSMAC CS Series Operation Manual page 200

I/O Communication Characteristics
PROFIBUS DP Cycle <
PLC Cyclic Refresh
Instruction
PLC Cycle
Execution
Slave I/O data refresh
PROFIBUS Cycle
Slave I/O data refresh
T
IN
ON
T Slave device Input ON (OFF) delay.
IN
T PROFIBUS I/O data exchange cycle time
PB,Cyc
(See Appendix A Bus Parameters)
T I/O Processing time in the Master Unit. Minimum value is 430 µs,
M,Proc
but may increase with increasing I/O data size.
T Master request cyclic refresh until actual start of cyclic refresh.
M,Rrf
T PLC cycle time (See section 6-5-5 PLC Cycle Time Performance).
PLC,Cyc
T PLC cyclic refresh time (See section 6-5-5).
PLC,Rf
T Slave device Output ON (OFF) delay.
OUT
The total I/O response time is the sum of all components:
T = T + 4*T
IO IN PB,Cyc
Note The calculation assumes the presence of only one Master Unit on the PROFI-
BUS network.
The figure below shows the timing in case the PROFIBUS DP cycle < PLC
cyclic refresh.
Instruction
Execution
T T
PB,Cyc PB,Cyc
T + T
M,Proc M,Rrf
T Slave device Input ON (OFF) delay.
IN
T PROFIBUS I/O data exchange cycle time
PB,Cyc
(See Appendix A Bus Parameters)
T I/O Processing time in the Master Unit.
M,Proc
T Master request cyclic refresh until actual start of cyclic refresh.
M,Rrf
T PLC cycle time (See section 6-5-5 PLC Cycle Time Performance).
PLC,Cyc
T PLC cyclic refresh time (See section 6-5-5).
PLC,Rf
T Slave device Output ON (OFF) delay.
OUT
The total I/O response time is the sum of all components:
T = T + 4*T
IO IN PB,Cyc
+ 2*T + T + 2*T
M,Proc M,Rrf
Instruction Instruction
Execution Execution
T T
PLC,Cyc PLC,Cyc
+ 2*T + T + 2*T
M,Proc M,Rrf
Section 6-5
+ T + T
PLC,Cyc PLC,Rf OUT
Instruction
Execution
T T
PB,Cyc PB,Cyc
T
M,Proc
T
PLC,Rf
+ T + T
PLC,Cyc PLC,Rf OUT
T
OUT
ON
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