LG GLOFA-GM Series User Manual page 178

Chapter 7 Communication function
Remark
Refer to technical spec. of GLOFA PLC for details to specify the area of each device in GLOFA GM.
[Note 1]
Ex.)
If the data type to write presently is DOUBLE WORD and the data to write is H12345678, its ASCII code converted
value is 3132333435363738, which shall be input in data area. Namely, the highest value shall be transmitted first
and the lowest last.
Remark
[Notes1] Device data type of each block shall be surely identical.
[Notes2] If data type is BOOL, data to write is indicated by one byte of HEX. Namely, if bit value is 0, it is indicated
by H00(3030) and if 1, it is indicated by H01(3031).
2) Response format(for PLC of ACK 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(w), only one lower byte of the value resulted by adding 1 byte
each to ASCII values from ACK to ETX is converted into ASCII, added to BCC, and sent.
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(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.
Header Station No.
ACK H20
H06 H3230
Header Station No. Command
NAK H20 W(w)
H15 H3230 H57(77)
Command Command type
W(w) SS
H57(77) H5353
Command
type (HEX 2 Byte)
SS
H5353
7-59
Tail
ETX
H03
Error code
Tail
H4252 ETX
H34323532 H03
Frame check
BCC
Frame
check
BCC