Mitsubishi Electric MELSEC-Q Series User Manual page 166

(3) Setting method
Select the asynchronous mode or synchronous mode in "Scan Mode Setting" of the network parameter. (
Page 96, Section 7.3.1)
(4) Data flows in the asynchronous mode and synchronous mode
Data flows in the asynchronous mode and synchronous mode are explained below using examples of
communications between a master station and remote I/O station.
Even if latched device (listed in "CPU side device" in the table below) data are cleared to 0 using a program at reset of the
CPU module or at power off and on, the latched data may be output depending on the timing of a link scan and link refresh.
For how to prevent output of latched device data, perform actions listed in "How to disable the setting" in the table below.
Latch relay (L)
File register (R, ZR)
Extended data register (D) (Universal model QCPU only)
Extended link register (W) (Universal model QCPU only)
Device in the latch range
*1 For how to set an initial device value, refer to the manual for the CPU module used (function explanation, program
fundamentals).
(a) Data flow in the asynchronous mode
CPU module
(Sequence scan)
Master station buffer memory
(Remote input (RX))
Link scan
Response time of the corresponding station
Responses from remote
I/O stations
I: Delay time due to response delay of the remote I/O station
II: Delay time of transmission from the remote I/O station to the master station
III: Delay time between the master station receiving data and the data being stored into the buffer memory
IV: Delay time until information of the master station is refreshed in the CPU module
164
CPU side device
Response time of the first station
Response time of the final station
Input 1)
Clear the value of the device to 0 using the initial device
*1
value.
Delete all latch range settings.
Input 2) Input 3)
I II III
Transmission delay time
How to disable the setting
IV