LG GLOFA-GM Series User Manual page 203

Chapter 7 Communication function
3) Response format(for PLC of NAK response)
Format
Header
Name
Frame
NAK
(Ex.)
ASCII
H15
value
Station number, commands, type of command, frame No., and number of data are the same as in computer
request format.
BCC : When command is one of lower case(p), 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'.
If this response is received, re-start is required from the first with start command.
4) Example of use
In case frame NO is 255 and the number of data is H17 in station No.1.
(Computer request format)
Format
Header
Name
Frame (Ex.) ENQ
ASCII value H05
Remark
[Note 1] Frame No. and the number of data are indicated in HEX value.
(For PLC ACK response after execution of command)
Format
Header
Name
Frame (Ex.) ACK
ASCII value H06
Station Command
Command
No. type
H01 P(p) DX
H3031 H50(70) H4458
Station Command
Command
No. type
H01 P(p) DX
H3031 H50(70) H4458
Station Command
Command
No. type
H01 P(p) DX
H3031 H50(70) H4458
7-84
Frame No Number of
(HEX 4 data
Bytes) (HEX 1 Byte)
H0001 H10
H30303031 H3130
Number
Frame No.
of data
H00FF H17 H1055
H30304646 H3137 H31303535 34304641
Frame No. Number of data
H00FF
H30304646
Error code Frame
Tail
(HEX 2 Bytes) check
H1132 ETX BCC
H31313332 H03
Frame
Data Tail
check
40FA EOT BCC
H04
Frame
Tail
check
H17 ETX BCC
H3137 H03