Mitsubishi Electric MELSEC IQ-R series Reference Manual page 459

■Causes of transmission time (T1) delay
When a command that takes two scans to send is executed, the transmission time is twice the value obtained by the formula
above .
When the access request is issued to the same station from multiple external devices simultaneously, refer to the precautions
for data communication. (Page 23 When accessing CPU module)
Data transmission to the CPU module other than connected station (host station) on CC-Link IE,
MELSECNET/H, or MELSECNET/10 may be delayed considerably depending on conditions. The
transmission delay time can be shortened by limiting communication between an external device and the CPU
module to the station with C24/E71 mounted, and communicating with programmable controllers on other
stations by data link (LB, LW).
Transmission time (T1) to access other station (remote I/O net)
The following shows the transmission time for MELSECNET/H(remote I/O net) and MELSECNET/10(remote I/O net).
MELSEC iQ-R series and MELSEC-L series are not supported.
Transmission time (T1) = (Transmission delay time + 1 link scan time or internal processing time) × (n + 1)
Internal processing time C24 : Approximately 50 ms, E71 : Approximately 30 ms
*1 Refer to the transmission delay time in the reference manual (remote I/O network) of the network system.
*2 n=6
 When performing the initial communication to the relevant station after starting link.
 When communicating with stations other than the latest 16 stations communicated with.
n=1
 When performing the second communication when the number of communication stations is 16 or less
 When performing the second communication to the 16 stations communicated last
*3 When online program change is disabled in C24/E71, '1' is added only when writing data from external device.
(Set the parameter in the Switch Setting for C24. As for E71, set it in Operation Settings using Engineering tool.)
■Transmission time calculation example
The following example shows when C24 is mounted on the station on MELSECNET/H (remote I/O net), and the device
memory of other station on the same network is read. (When the number of communication station is 8 stations, and the
second communication is performed)
● Processing times
• S : Scan time of remote master station sequence program 12 ms
m
• 
: Link refresh time of remote master station 5 ms
m
• LS : Link scan time 9 ms
Since the processing time is (S
Ex.
When master station is one station
Transmission time (T1) = {(12 + 5) × 3 + 50} × 1
( 101ms )
*1 (When this value is more than the internal processing time.)
) > (LS), the transmission time (T1) will be as follows:
m
*2 *3
APPENDICES APPENDIX
Appendix 2 Processing Time
A
457