Chapter 8 Dedicated Communication
8-12
8.2.4 Write Continuous Direct Variable
(1) Introduction
This function is used to write the data on the directly defined PLC device memory continuously
as many as specified from the address specified. However, byte type of variables is only available.
(2) Request format
■ Write Request of Continuous Variable (MMI
PLC)
Item
Size(byte)
Description
Instruction
2
h0058 : Write Request
Data type
2
h0014 : Block Type
Reserved area
2
h0000 : Don’t Care.
Number of blocks
2
It is fixed with h0001 for Continuous write.
Variable length
2
The number of characters in the variable field; Max. 16
Variable
Variable
length
Variable name; Byte type of direct variables only available.
(In other words, types of %MB / %PB / %DB/… available:
supporting devices: P,N,L,K,T,C,D,N )
It displays block’s start address. (Ex. %MB0, %PB0)
Data
Data size
Data to write, up to 1400 bytes
Format
name
Header
Instruction
Data
type
Reserved
area
Number
of
blocks
Variable
length
Variable
Number
of data
Data
Code
(Ex.)
...
h0058
h0014
h0000
h0001
h0006
%MB1
00
h0002
h1234
1) Number of data
It means the number of data in byte unit. (up to 1,400(h0578) bytes available).
2) Number of blocks
h0001 only can be used for Number of blocks field .
3) Variable length
It is the number of characters of the variable which is available up to 16 characters, whose
range is h01 ~ h10.
4) Variable
It stands for variable’s address to write actually. It shall be ASCII value within 16 characters.
Others than figure, capital/small letter, ‘%’ and ’.’ are not allowed for the variable name.
Based on the PLC type, types of variables available to write continuously are described in
[Table 10.3.2].
Notes
(1) Refer to applicable technical materials for respective device areas setting of XGT series.
