Chapter 13. Dedicated Cnet communication for GM6
13 - 19
(4) Response format(for NAK response)
Format name
Header
Station
No.
Command
Command
type
Error code
(Hex 2 Bytes)
Tail
Frame check
Frame(Ex.)
NAK
H20
W(w)
SS
H4252
ETX
BCC
ASCII value
H15
H3230
H57(77)
H5353
H34323532
H03
•
Station number, commands, and type of command are the same as computer request format.
•
BCC : When command is one of lower case(w), 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.
•
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
This supposes that "H00FF" is written in %MW230 address.
(Computer request format)
Format
name
Head-
er
Station
No.
Command
Command
type
Number of
blocks
Variable
name
length
Variable
name
Data
Tail BCC
Frame
(Ex.)
ENQ
H01
W(w)
SS
H01
H06
%MW230
H00FF
EOT BCC
ASCII
value
H05
H3031
H57(77)
H5353
H3031
H3036
H254D573
23330
H303046
46
H04
(For PLC ACK response after execution of command)
Format
name
Header
Station No.
Command
Command type
Tail BCC
Frame
(Ex.)
ACK
H01
W(w)
SS
ETX BCC
ASCII
value
H06
H3031
H57(77)
H5353
H03
(For PLC NAK response after execution of command)
Format
name
Header
Station
No.
Command
Command type
Error code
Tail BCC
Frame
(Ex.)
NAK
H01
W(w)
SS
Error code(2)
ETX BCC
ASCII
value
H15
H3031
H57(77)
H5353
Error code(4)
H03