Chapter 13. Dedicated Cnet communication for GM6
13 - 13
2)
Continuous reading(RSB) of direct variable
(1) Introduction
This is a function that reads the PLC device memory directly specified in accord with memory data type. With
this, data is read from specified address as much as specified.
(2) Request format
Format
name
Header
Station
No.
Command
Command
type
Variable
length
Variable
name
Number of data
(Max.120 Bytes)
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
•
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, added to BCC.
•
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).
•
Direct variables :
Address to be actually read is entered in this. This must be ASCII value within 16 characters,
and in this name, digits, upper/lower case, '%' and '.' only are allowable to be entered. Continuous reading of
direct variables available according to PLC type are as follows :
Number of data specifies the number according to the type of direct variable. Namely, if the data type of direct variable
is double word, and number of data is 5, it means that read 5 DOUBLE WORDs.
Remark
