268
6-4
.
Communication flag and register
Communication flag
Serial
port
Register address Function
Explanation
Port 0
SM140
Modbus read-write
instruction execution flag
When the instruction starts to
execute, set ON
When execution is completed,
set OFF
SM141
SM142
Free communication sending
flag
When the instruction starts to
execute, set ON
When execution is completed,
set OFF
SM143
Free communication received
flag
When receiving a frame of data
or receiving data timeout, set
ON.
Require user program to set OFF
SM144
……
SM149
Port 1
SM150
Modbus read-write
instruction execution flag
When the instruction starts to
execute, set ON
When execution is completed,
set OFF
SM151
SM152
Free communication sending
flag
When the instruction starts to
execute, set ON
When execution is completed,
set OFF
SM153
Free communication received
flag
When receiving a frame of data
or receiving data timeout, set
ON.
Require user program to set OFF
SM154
……
SM159
Port 2
SM160
Modbus read-write
instruction execution flag
When the instruction starts to
execute, set ON
When execution is completed,
set OFF
SM161
SM162
Free communication sending
flag
When the instruction starts to
execute, set ON
When execution is completed,
set OFF
SM163
Free communication received
flag
When receiving a frame of data
or receiving data timeout, set
ON.
Require user program to set OFF
SM164
……