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Chapter 7 Communication function
7-69
4)
Response format(for PLC NAK response)
Format
Name
Header
Station
No.
Command
Registration
No.
Error code(HEX 2Byte)
Tail
Frame check
Frame(Ex.) ACK H10 X(x)
H1F
H1132
ETX BCC
ASCII value
H06
H3130
H58(78)
H3146
H31313332
H03
9
Station number, commands, and register No. are the same as in computer request format.
9
BCC : When command is one of lower case(x), only one lower byte of the value resulted by adding 1 byte
each to ASCII values from NAK to ETX is converted into ASCII, added to BCC, and sent.
9
Error code is HEX and 2 bytes(ASCII code, 4 bytes), which indicates type of error. For the details, see
Appendix ‘B. Error Code Table’.
5)
Example of use
In case of monitor registration of No.1 in station No.1 with data type of uint and variable name of “ASDF”.
(Computer request format)
Registered format
Format
Name
Header
Station
No.
Command
Registration
No
R##
Number of
blocks
Variable
length
Variable
name
Tail
Frame
check
Frame (Ex.)
ENQ
H01 X(x) H01 R0A H01
H04 ASDF EOT
BCC
ASCII value
H05
H3031
H58(78)
H3031 H523041
H3031 H3034
H41534446
H04
(For PLC ACK response after execution of command)
Format
Name
Header
Station No.
Command
Registration No
Tail
Frame check
Frame (Ex.)
ACK
H01
X(x)
H01
ETX
BCC
ASCII
value
H06 H3031
H58(78)
H3031 H03
(For PLC NAK response after execution of command)
Format
Name
Header
Station No.
Command
Command type
Error code
Tail
Frame
check
Frame (Ex.)
NAK
H01
X(x)
H01
Error code(2)
ETX
BCC
ASCII value
H15
H3031
H58(78)
H3031
Error code(4)
H03