LG GLOFA-GM Series User Manual page 196

Chapter 7 Communication function
3) Response format(for PLC of NAK response)
Format
Name
Frame (Ex.)
ASCII value
Station number, commands, and type of command are the same as in computer request format.
BCC : When command is one of lower case(m), 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'.
4) Example of use
In case PI name is executed as specified to PLC_RUN in the state that Domain name has been downloaded in
PGM of PLC.
(Computer request format)
Format
Header
Name
Frame (Ex.) ENQ
ASCII value H05
(For PLC ACK response after execution of command)
Format
Header
Name
Frame (Ex.)
ASCII value
(For PLC NAK response after execution of command)
Format
Header
Name
Frame (Ex.)
ASCII value
Station
Header Command
No.
NAK H10 M(m)
H15 H3130 H4D(6D)
Station Comman Command
No. d type
H01 M(m) CN
H3031 H4D(6D) H434E
Station No.
ACK H01
H06 H3031
Station No.
NAK H01
H15 H3031
Command type
(HEX 2 Byte)
CN
H434E H31313332
PI_N_ LEN PI_N_NAME
H07 PLC_RUN
H3037 H504C435F52554E
Command Command type
M(m) CN
H4D(6D) H434E
Command Command type
M(m) CN
H4D(6D) H434E
7-77
Error code
Tail
H1132 ETX
H03
DM_LEN DM_NAME
H03 PGM
H3033 H50474D
Tail
ETX
H03
Error code Tail
Error code(2) ETX
Error code(4) H03
Frame check
BCC
Frame
Tail
check
EOT BCC
H04
Frame check
BCC
Frame check
BCC