Programming language – Toshiba T2N User Manual
Page 216
5. Programming Language
User's manual
203
The rung numbers are a series of numbers (decimal numbers) starting
from 1, and rung numbers cannot be skipped. There is no limit to the
number of rungs.
The size of any one rung is limited to 11 lines x 12 columns, as shown
below.
Ladder diagram is a language which composes programs using relay
symbols as a base in an image similar to a hard-wired relay sequence.
In the T2N, in order to achieve an efficient data-processing program,
ladder diagram which are combinations of relay symbols and function
blocks are used.
Relay Symbols ... These are NO contacts, NC contacts, coils and
contacts and coils to which special functions are
given. Each of these is called an ‘instruction’.
(Basic ladder instructions)
Example)
NO contact
Input
Output
When device A is ON, the input side and the output side become
conductive.
Viewed from the aspect of program execution, the operation is such that
when the input is ON and the content of device A is also ON, the output
will become ON.