LG GLOFA-GM Series User Manual page 174

Chapter 7 Communication function
1 Reading of PLC STATUS (RST)
This is a function to read flag list such as operation status and error information of PLC.
1) Request format(PC -> PLC)
Format
Header
name
Frame(Ex.)
ENQ
ASCII
H05
value
BCC : When command is one of lower case(r), only one lower byte of the value resulted by adding 1 byte
each to ASCII values from ENQ to EOT is converted into ASCII and added to BCC.
2) Response format(for PLC of ACK response)
Format
Header
name
Frame(Ex.)
ACK
ASCII
H06
value
Station number, commands, and type of command are the same as in computer request format.
BCC : When command is one of lower case(r), 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.
STATUS data format : This status format is converted into ASCII code of total 20 bytes in HEX. And Its
contents after converted to HEX data from ASCII code are composed as below.
[Table7.20] STATUS data Format
Data type
UINT
Byte
Byte
Byte
Byte
Station No.
H0A
H3041
Station No. Command Command type
H0A R(r)
H3041 H52(72)
Flag name
PC_DEVICE_IDENTIFIER;
Logical;
[Note 1]
Physical;
[Note 1]
_CPU_TYPE;
_VER_NUM;
7-55
Command Command type
R(r) ST
H52(72) H5354
STATUS data
(HEX 20 Byte)
ST STATUS data format
[※]
H5354
Status data sequence(HEX data)
H00(L) ~ H01(H)
[Note 1]
H02(Offset)
H03
H04
H05
Tail Frame check
EOT BCC
H04
Tail
Frame check
ETX BCC
H03