
B-63983EN/02 4.LADDER LANGUAGE
- 211 -
(8) Addresses of numeric data processed by functional instructions
When the numeric data to be processed by a functional
instruction consists of two or four bytes, it is recommended to
specify an even number or a multiple of four as the address of the
numeric data in the relevant parameter of that functional
instruction. Specifying an even-numbered or multiple-of-four
address causes the functional instruction to execute slightly faster.
In the case of a functional instruction that mainly deals with
binary data, such a parameter is marked with an asterisk (*) in
the parameter field of the diagram illustrating the format of the
functional instruction, as shown below.
An even-numbered or multiple-of-four address means that the
letter R is followed by an even number or a multiple of four in
the case of an internal relay, or that the letter D is followed by an
even number or a multiple of four in the case of a data table.
Error out
ut
RST
W1
CT
DDB
SUB36
¡¡¡¡ Format
*
¡¡¡¡
Summand data address
*
¡¡¡¡
ddend data
address
*¡¡¡¡
Addition result out
ut address
* When the numeric data consists of two or four bytes, specify an even-numbered or multiple-of-four address
for each of those addresses marked with *. Doing so causes the functional instruction to execute faster.
Fig. 4.2.1 (b)