R-2-2 Communications Specifications; R-2-3 Transmission Procedure; R-2-4 Command And Response Formats - Omron CJ1W-SCU32 Operation Manual

A Standard System Protocol
R-2-2 Communications Specifications
Item
Transmission path con-
nections
Communications
Synchronization
Baud rate
Transmitted code
Data length
Stop bits
Error detection
R-2-3 Transmission Procedure
The PLC or host computer serving as the master sends a command and the component serving as the
slave returns a response for the command message contained in the command. One response mes-
sage is returned for each command message. The movement of command and response messages is
shown below.
Master (PLC or host computer)
Slave (component)
R-2-4 Command and Response Formats
Note In the following diagrams "Hex" indicates hexadecimal values. Values in quotation marks, such
as "00" indicate ASCII characters.
Command Frame
1 byte
Response Frame
1 byte
Note 1 Data is not saved in the response if there is a command frame error (i.e., if the end code is
not 00 or 0F).
2 Other values are possible for the subaddress and SID.
R-8
Multipoint
RS-232C, RS-422A/485, 4-wire half-duplex, 2-wire half-duplex
Start-stop
1,200/2,400/4,800/9,600/19,200/38,400 bps
Default: 9,600 bps
ASCII
7 bits or 8 bits (Default: 7 bits)
Note: A 7-bit code is used with 0 added to the beginning.
1 bit or 2 bits (Default: 2 bits)
Vertical parity (none, even, or odd) (Default: Even)
BCC (block check character)*
*: Start-stop Sync Data Configuration for Protocol Macros
LRC, 1 byte, equivalent to binary
Command message
Node No.
Subaddress
"00"
"0"
2 bytes 2 bytes 1 byte
Node No. Subaddress End code
"00"
"00"
2 bytes 2 bytes 2 bytes
CJ-series Serial Communications Units Operation Manual for NJ-series CPU Unit(W494)
Specification
Response message
Text
Command
Data
1 byte
1 byte
Response
Text
Data
(See note.)
1 byte 1 byte