Rievtech PR-12 Series, User Manual And Programmers Manual

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5.8 PLC operation and options
Elements of the control program
Ladder Program
In the LAD program, the basic elements of the logic are represented by contacts, coils,
and boxes.
The input is represented by a symbol called a contact.Contact is divided into normally
open contact and normally closed contact.
Normally open contact: a contact that is open in nature.
Normally closed contact: a contact that is closed in nature.
The output is represented by a symbol called a coil.
The blocks are function blocks with various functions.The blocks can make
programming easier.
STL program
The STL program elements are represented by instructions.Ladder diagram and
instructions are as follows:
System blocks configuration
Instructions
：
The detailed annotation of operation interface
--->
System blocks