Yokogawa Value Series FX1000 - Manual (Page 191)

App-1
IM 04L21B01-17EN
Appendix
1
2
3
4
5
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App
Index
Appendix 1 Data Dropout during Modbus
Communication
Data Dropout during Modbus Client
If the response to the previous command is not complete when the FX attempts to
issue a command to a server device, the FX cannot issue the command causing a data
dropout. Take appropriate measures by referring to the following figures.
Read cycle
Data dropout
(Servers 2 and 3)
Data dropout
(Server 3)
Server device 1
Server device 2
Server device 3
G
G
G
G
G
G
Read cycle
(Retry)
: Status lamp
: Response from the server device
: Command from the FX
Data dropout
(Servers 2 and 3)
Server device 1
Server device 2
Server device 3
Read cycle
Timeout value
Connection dropped
Data dropout
(Servers 2 and 3)
Server device 1
Server device 2
Server device 3
G G
G
G
G
G G
O
Connection dropped Connection recovered
Timeout value
G
G
G
G
O
Y
Connection retry time 1
G G
G G G
G
Y
O R
1. When the response from the server device takes a long time
2. When the connection is dropped because there is no response from the server device
3. When the communication recovers by connection retry
1: The first connection retry after the connection is
dropped is shorter than the specified interval.
The status lamp condition is an example when
connection retry is configured.
Appendix