Omron CJ1W-SCU22, Руководство по эксплуатации, Страница: 228 / 478

5 Serial Gateway
5-36
CJ-series Serial Communications Units Operation Manual for NJ-series CPU Unit(W494)
z
Command Frame
z
Response Frame
5-6-3 Modbus-ASCII
Frame before Conversion
Header Command
Remote
network
address
(DNA) Remote
node
address
(DA1) Remote
unit
address
(DA2) MRC
Serial port
allocated
address 00 hex Serial
port
unit
address
or local
network
address
28 05
or local
network
node
address
Modbus-ASCII
(command section only)
Slave
address
(ASCII code
2 characters:
2 bytes) FUNCTION
code
(ASCII code
2 characters:
2 bytes) Communications data
(ASCII code n characters)
Header
":"
(ASCII code
3A hex) FUNCTION code
(ASCII code
2 characters:
2 bytes) CR
(0D hex)
Modbus-ASCII frame
Communications data
(ASCII code n characters) LF
(0A hex) Slave address
(ASCII code
2 characters:
2 bytes)
Frame after Conversion
SRC Etc.
LRC
(2 ASCII
characters:
2 bytes)
Frame before Conversion
Modbus-ASCII frame
Header
":"
(ASCII code
3A hex) Slave address
(ASCII code
2 characters:
2 bytes)
Remote
network
address
(DNA)
FUNCTION code
(ASCII code
2 characters:
2 bytes) Communications data
(ASCII code n characters)
or error code
CR
(0D hex)
Command Header
Remote
node
address
(DA1)
28 05
Remote
unit
address
(DA2)
LF
(0A hex)
Command
end code
or local
network
address or local
network
node
address
Serial port
allocated
address
SRC
Modbus-ASCII
(command section only)
MRES SRES
Slave
address
(ASCII code
2 characters:
2 bytes)
MRC
Frame after Conversion
00 hex Serial
port
unit
address
FUNCTION
code
(ASCII code
2 characters:
2 bytes) Communications data
(ASCII code n characters)
or error code
Etc.
User-
speci-
fied User-
speci-
fied
LRC
(2 ASCII
characters:
2 bytes)