Omron CJ - REFERENCE MANUAL 07-2009 User Manual

9
Command/Response Formats Section 2-2
the following transmissions until the number of words set in the command has
been processed.
The frame formats for Host Link commands sent from a host computer and
responses returned by the PLC receiving the commands are explained in the
following section.
2-2 Command/Response Formats
Single-frame Commands If a command is not more than 131 characters long, communications can be
completed by sending a single command frame. This is called a “single-frame
command.”
Command Frame Format
• @: Must be attached at the beginning of the command.
• Unit number: Set in BCD from 0 to 31 for each Host Link Unit.
• Header code: Specified in two characters.
• Text: Set parameters corresponding to command code.
• FCS: Calculate 2-character FCS (frame check sequence) at host
computer. For details on calculating FCS, refer to FCS Cal-
culations later in this section.
• Terminator: Set “*” and CR (CHR$(13)) as two characters to indicate
the end of the command.
Single-frame Response If a response is not more than 131 characters long, the communications can
be completed by returning one response frame. This is called a “single-frame
response.”
Response Frame Format
• @: Must be attached at the beginning of the response.
• Unit number: Set in BCD from 0 to 31 for each Host Link Unit.
• Header code: The command code that was received is returned.
• End code: The results (error status, etc.) of command execution is
returned.
• Text: Returned only if there is read data.
Unit number (BCD)
Header code
Text
FCS
Terminator
Unit number
(
BCD
)
End code (hexadecimal)
Text
FCS
Terminator
Header code

Omron CJ - REFERENCE MANUAL 07-2009 Specifications

General

Brand	Omron
Model	CJ - REFERENCE MANUAL 07-2009
Category	Computer Hardware
Language	English