Chapter 13. Dedicated Cnet communication for GM6
13 - 9
13.7
Execution of commands(Ex.)
1) Separately reading(RSS) direct variables
(1) Introduction
This is a function that reads PLC device memory directly specified in accord with memory data type.
Separate device memory can be read up to 4 at a time.
(2) Request format(PC-->PLC)
Format
name
Header
Station
No.
Command
Comman
d type
Number
of
blocks
Variable
length
Variable
name
Tail
Fame
check
Frame
(Ex.)
ENQ
H20
1)
R(r)
SS
H01
H06
%MW100
..........
EO
T
BCC
ASCII
value
H05
H3230
H52
(72)
H5353
H3031
H3036
H254D573130
30
H04
1 block(Setting can be repeated up to 4 block)
•
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.
•
Number of blocks : This specifies how much of the blocks composed of '[Variable length][Variable name]' are in
this request format. This can be set up to 4. Therefore, the value of [Number of blocks] must be
H01(ASCII value:3031)-H04(ASCII value:3034).
•
Variable length(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. This must be ASCII value within 16 characters, and in
this name, digits, upper/lower case, '%' and '.' only are allowable to be entered.
1) Numerical data of frame(Ex.) is hex value, and 'H' is unnecessary during preparing real frame.
Remark
