Transmission Time When Accessing Other Stations - Mitsubishi Electric MELSEC IQ-R series Reference Manual

Transmission time when accessing other stations

This section explains the transmission time (T1) when accessing CC-Link IE, MELSECNET/H, or MELSECNET/10 on other
station.
For details on the network systems, refer to the manual of each network system.
Transmission time (T1) to access other station (CC-Link IE, PLC network)
The following formula is for calculating the transmission time of CC-Link IE, MELSECNET/H (PLC network), and
MELSECNET/10 (PLC network).
Transmission time (T1) = (Transmission delay time + 1 scan time of the station on which the C24/E71 is loaded 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 manual of the network system.
*2 n=6
 When performing the initial communication to the relevant station after powering ON or resetting CPU
 When performing communication to stations excluding the currently communicated 16 stations
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 "Online change" with the "Switch setting" or "Parameter setting" of Engineering tool.)
■Transmission time calculation example
The following example shows when C24 is mounted on the station on CC-Link IE controller network, 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 and settings
• S : Scan time of transmission side 2 ms
T
• S : Scan time of reception side 1 ms
R
• LS : Link scan time 2 ms
• 
: Link refresh time of transmission side 1 ms
T
• 
: Link refresh time of reception side 1 ms
R
• Simultaneous transient request: 2
• Maximum transient request: 1
Ex.
Normal transmission delay time
Transmission time (T1) = {(2 + 1 + 1 + 1) × 2 + 2 ×4 + (2 / 1 - 1) × 2 × 2 + 50} × 1
( 72ms )
Simultaneous transient request
Maximum transient request
C24 internal processing time
Ex.
Worst-case transmission delay time
Transmission time (T1) = {(2 + 1 + 1 + 1) × 2 + 2 × 6 + (2 / 1 - 1) × 2 × 2 + 50} × 1
( 76ms )
Simultaneous transient request
Maximum transient request
C24 internal processing time
APPENDICES APPENDIX
456
Appendix 2 Processing Time
*1 (When this value is more than the internal processing time.)
( LS ) ( LS )
( LS ) ( LS )
*2 *3