Chapter 13. Dedicated Cnet communication for GM6
13 - 20
4)
Continuous writing of direct variable(WSB)
(1) Introduction
This is a function that directly specifies PLC device memory and continuously writes data from specified
address as much as specified length.
(2) Request format
Form-
at
name
Head-
er
Stat-
ion
No.
Comm-
and
Comm
-and
type
Variable
length
Variable
name
Number of data
(Max.120 Bytes)
Data
Tail
Frame
check
Frame
(Ex.)
ENQ
H10
W(w)
SB
H06
%MD100 H01
H1111222
2
EOT BCC
ASCII
value
H05
H3130
H57
(77)
H5342
H3036
H254D44
313030
H3031
H3131313
132323232
H04
•
BCC : When command is one of lower case(w), 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.
•
Protocol of continuous writing function of direct variable has not [Number of blocks].
•
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.
Direct variables available according to PLC type are as follows :
1) 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 write 5 DOUBLE WORDs.
Remark
