Modbus-Rtu - Omron SYSMAC CS1W-SCB41-V1 Operation Manual

Communications Frames
Response Frame
6-8-2

Modbus-RTU

Command Frame
Note
238
Further, to write the CompoWay/F command to the command storage area
using CMND(490) in frame order (without creating empty bytes), the SID com-
ponent of the CompoWay/F command requires 1 byte of ASCII as 30 hex, so
the subsequent components (s+3 and afterwards) must be set in one byte
each.
Frame before Conversion
CompoWay/F
STX Node No. Sub- End code Command
(× 10 1 )
address (MRC,
(02 hex) (ASCII
2
(× 10 ) "00" SRC)
code
(ASCII (ASCII (ASCII
8 bytes)
code code code
4 bytes) 3030 8 bytes)
hex) etc.
Frame after Conversion
FINS header FINS command FINS end code
Remote Remote Remote MRC SRC MRES SRES
unit ad-
network node
dress
address address
(DA2)
(DNA) (DA1)
etc.
03 User- User-
Serial 00 hex Serial 28
port port unit speci- speci-
fied fied
allocated address
address
Frame before Conversion
FINS header FINS command
Remote Remote Remote Etc. MRC
network node unit
address address address
(DNA) (DA1) (DA2)
Serial port 00 hex Serial 28
allocated port
address unit
address
or local or local
network network
address node
address
Frame after Conversion
Start (silent Slave FUNCTION
interval of
address code
3.5
(1 byte) (1 byte)
characters)
(See note.)
The silent interval in the Modbus-RTU frame is automatically generated by the
Serial Communications Board/Unit.
Response Text ETX BCC
(MRES,
(ASCII (03 hex)
SRES)
code)
(ASCII
code
8 bytes)
CompoWay/F
(See note.)
Node No. Sub- End code Command Response
(× 10 1 )
address (MRC, (MRES,
(ASCII
2 "00" SRC) SRES)
(× 10 ) code
(ASCII code (ASCII (ASCII
(ASCII code 2 bytes)
3030 hex) code code
2 bytes) etc. 4 bytes) 4 bytes)
Modbus-RTU
SRC
(command section only)
04 Slave FUNCTION
address code(1 byte)
(1 byte)
Modbus-RTU frame
Communications data Error
(n bytes) check
CRC
(1 byte)
Section 6-8
Text
(ASCII
code)
Communications data
(n bytes)
End (silent
interval of
3.5
characters)
(See note.)