LG GLOFA-GM Series, Руководство пользователя, Страница: 165 / 358

Chapter 7 Communication function
7-46
1 Continuous reading of direct variables (RSB)
This is a function to read PLC device memory directly specified in accord with memory data type.
It is convenient command to continuously read data up to 120 bytes in continuous areas from the specified
address.
1) Request format(PC -> PLC)
Format
Name
Header
Station
No.
Command
Command
type
Variable
length
Variable
name
Number of data
(Max.120 byte)
Tail
Frame
check
Frame(Ex.) ENQ H10 R(r) SB H06 %MD100 H05 EOT BCC
ASCII value H05 H3130 H52(72) H5342 H3036
H254D44
313030
H3035 H04
Remark
[Note 1] Number of data specifies the number
according to the type of direct variable. Namely, if data type of direct
variable is double word and the number of data is 5, it means that 5 double
words shall be let read.
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.
9 Name length of direct variable : This indicates the number of name’s characters that means direct variable,
which is allowable 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 Direct variable : It means address of variable to be read actually in ASCII value within 16 characters. Others
than figure, upper/lower cases, ‘%’ and ’.’ are not allowed for this variable name. Variable type available for
continuous reading of direct variables is as follows according to PLC type.
[Table7.17] Continuous variable area available to read
Classification BOOL Byte WORD DOUBLE WORD LONG WORD
GM1 - %MB,%QB,%IB %MW,%QW,%IW %MD,%QD,%ID %ML,%QL,%IL
GM2 - %MB,%QB,%IB %MW,%QW,%IW %MD,%QD,%ID %ML,%QL,%IL
GM3 - %MB,%QB,%IB %MW,%QW,%IW %MD,%QD,%ID -
GM4 - %MB,%QB,%IB %MW,%QW,%IW %MD,%QD,%ID -
GM6 - %MB,%QB,%IB %MW,%QW,%IW %MD,%QD,%ID -
GM7 - %MB,%QB,%IB %MW,%QW,%IW %MD,%QD,%ID -