LG GLOFA-GM Series, Руководство пользователя, Страница: 161 / 358

Chapter 7 Communication function
7-42
7.2.5 Execution of commands (Ex.)
1 Individual reading of direct variables (RSS)
This is a function to read PLC device memory directly specified in accord with memory data type.
Separate device memories can be read up to 4 at a time.
1) Request format(PC -> PLC)
Header
Station
No.
Comm-
and
Command
type
Number of
blocks
Variable
length
Variable
name
Tail
Frame
check
Frame(Ex.) ENQ H20
[Note 1]
R(r) SS H01 H06 %MW100
Repea-
ted
block
EOT BCC
ASCII
value
H05 H3230 H52(72) H5353 H3031 H3036
H254D57
313030
H04 H4134
1 block(Setting can be repeated up to 4 blocks)
9
Number of blocks: This specifies the number of the blocks composed of ‘[Variable length][Variable name]’
in this request format. This can be set up to 4 blocks. Therefore, the value of [Number of blocks] must be
H01(ASCII value:3031)-H04(ASCII value:3034).
9
Variable length(name length of direct variable) : This indicates the number of name’s characters that means
direct variable, which is allowed up to 16 characters. This value is one of ASCII converted from HEX type,
and the range is from H01(ASCII value:3031) to H10(ASCII value:3130).
9
Variable name : Input address of variable to be read actually in ASCII value within 16 characters. Others
than figure, upper/lower cases, ‘%’ and ’.’ are not allowed for variable name.
9
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.
Remark
[Note 1] Numerical data of frame(Ex.) is HEX value, and ‘H’ is unnecessary during preparing real frame.
FORMAT
NAME