Convert To Modbus-Rtu Command: 28 04 - Omron CJ - REFERENCE MANUAL 07-2009 Reference Manual

FINS Commands

5-3-47 CONVERT TO MODBUS-RTU COMMAND: 28 04

Execution Conditions
Command Format
Response Format
Parameters
Note For CompoWay/F, set SID 0 (1-byte ASCII: 30 hex) in the leftmost
byte of S+3 and the most significant digit of the CompoWay/F com-
mand code's MRC (1-byte ASCII) in the rightmost byte of S+3. Set
the least significant digit of the CompoWay/F command code's MRC
(1-byte ASCII) in the leftmost byte of S+4 and the most significant
digit of the CompoWay/F command code's SRC (1-byte ASCII) in the
rightmost byte of S+4. Be sure to set the remaining data with this 1-
byte offset as well.
When this command is sent to serial port 1 or 2 on an Option Board of a CP-
series CPU Unit, or a serial port on a Serial Communications Unit/Board (ver-
sion 1.2 or later), the CPU Unit or Serial Communications Unit/Board removes
the FINS header and sends the enclosed Modbus-RTU command.
With this command, OMRON components connected to a PLC through Mod-
bus-RTU communications can be accessed from a PLC or PT by sending a
FINS message containing a Modbus-RTU command.
Access right at
other device
OK
RUN mode
OK
28 04
Command Slave Function
code address code
28 04
Command End code Slave
code address
Command
Slave Address
Specify the Modbus-RTU device address. Set the address in hexadecimal
between 01 and F7 hex (1 to 247 decimal).
Function Code
Specify the function code of the Modbus-RTU command. Set the address in
hexadecimal between 01 and FF hex (1 to 255 decimal).
Communications Data
Specify the required parameters associated with the function code. The
amount of communications data varies. (In some cases, there is no communi-
cations data.)
Response
The response is the same as the command except that it contains an end
code.
UM read DIP switch UM write
protection protection
OK
MONITOR mode
OK
Communications
data
Function Communications
code data
Section 5-3
Network write
protection
OK OK
PROGRAM mode
OK
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