Communication Cycle Time; Transmission Delay Time - Mitsubishi Electric MELSEC iQ-R Series User Manual

Communication cycle time

The communication cycle time is an interval between the following operations: the master node issues a polling or bit strobe
type request to a slave node, and the master node issues another request to the same slave node.
The communication cycle time for each slave node can be calculated with the following calculation formula.
• For LS < PIT: LC = LS + PIT [ms]
• For LS  PIT: LC = LS [ms]
LC: Communication cycle time [ms]
LS: Link scan time [ms] ( Page 95 Link scan time)
PIT: Production inhibit time [ms] ( Page 86 Master function parameters (Un\G468 to Un\G975))

Transmission delay time

The transmission delay time varies depending on whether the data consistency dedicated instruction is used.
The following symbols are used in each calculation formula for explanation.
ST: Sequence scan time [ms]
LS: Link scan time [ms] ( Page 95 Link scan time)
PIT: Production inhibit time [ms] ( Page 86 Master function parameters (Un\G468 to Un\G975))
LC: Communication cycle time [ms] (For LS < PIT: LC = LS + PIT [ms], for LS  PIT: LC = LS [ms])
When the data consistency dedicated instruction is not used
The following table shows the transmission delay time for performing refresh or reading/writing I/O data with the MOV
instruction or the FROM/TO instruction.
■Transmission delay time of transmit data
Item
Normal value
Maximum value
■Transmission delay time of receive data
Item
Normal value
Maximum value
When the data consistency dedicated instruction is used
The following table shows the transmission delay time for reading/writing I/O data with the dedicated instruction.
■Transmission delay time of transmit data
Item
Normal value
Maximum value
■Transmission delay time of receive data
Item
Normal value
Maximum value
APPX
96
Appendix 4 Processing Time
When writing transmit data with a program (with the TO instruction)
LC0.5+LS0.5 [ms]
LC+LS [ms]
When reading receive data with a program (with the FROM instruction)
LC0.5+LS0.5+ST0.5 [ms]
LC+LS+ST [ms]
Condition When writing transmit data with a program
STLS ST0.5+LS1.5+LC0.5 [ms]
LS < ST ST1.5+LS+LC0.5 [ms]
ST + LS  2 + LC [ms]
STLS
LS < ST ST2+LS+LC [ms]
Condition When reading receive data with a program
2STLS ST0.5+LS0.5+LC0.5 [ms]
ST  LS < 2ST
ST3.5+LC0.5 [ms]
LS < ST ST2.5+LC0.5 [ms]
2STLS ST+LS+LC [ms]
ST  LS < 2ST
ST4+LC [ms]
LS < ST ST3+LC [ms]
When performing refresh
LC0.5+LS0.5+ST0.5 [ms]
LC+LS+ST [ms]
When performing refresh
When performing refresh
LS  1.5 + LC  0.5 - ST  0.5 [ms]
ST  0.5 + LS  0.5 + LC  0.5 [ms]
LS  2 + LC [ms]
ST + LS + LC [ms]
When performing refresh
ST0.5+LS0.5+LC0.5 [ms]
ST1.5+LC0.5 [ms]
ST+LS+LC [ms]
ST2+LC [ms]