NAiS FP Series User Manual page 151

Communication Function 1 Computer Link
Notes
Precautions when writing messages
The method for writing text segments in the message varies
depending on the type of command.
If there is a large number of characters to be written, they may
be divided and sent as several commands. If there is a large
number of characters in the value that was loaded, they may
be divided and several responses sent.
Response message
The PLC that received the command in the previous page sends the results of the
processing to the computer.
Start code
1
Unit No. of source (PLC that processed the command, in decimal)
2
%
0 1 $ R
or
<
(One -
(Two -
digit)
digit)
Response code ($ indicates a normal processing result; ! indicates that an error occurred)
Figure 144: FPΣ Response message (format)
Start code (Header)
1
A "%" (ASCII code: H25) or "<" (ASCII code: H3C) must be at the beginning of a message.
The response must start with the same start code that was at the beginning of the command.
Unit No.
2
The unit number of the PLC that processed the command is stored here. If 1:1
communication is being used, "01" will be stored here.
Text
3
The content of this varies depending on the type of command. The value should be read
based on the content. If the processing is not completed successfully, an error code will be
stored here, so that the content of the error can be checked.
0 1 $ R
%
Response code
If normal: "#" (ASCII code: H23)
If error occurs: "!" (ASCII code: H21)
Figure 145: FPΣ Response message (text)
8 - 6
Text (Processing results and communication error codes are stored here)
3
Check code (BCC, Hexadecimal)
4
C
C 0
R
Read value (specified contact is off)
Command name (Processing results for contact area read)
C
C 1 2 1
R
If the read command was used, the data that was read is stored here.
If normal: Command name
If error occurs: Error code
End code
5
FPΣ