Using Boolean Instructions; End Statement; Simple Rungs - Automationdirect.com DL05 User Manual

Chapter 5: Standard RLL Instructions

Using Boolean Instructions

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Do you ever wonder why so many PLC manufacturers always quote the scan time for a
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1K Boolean program? Simple. Most all programs utilize many Boolean instructions. These
are typically very simple instructions designed to join input and output contacts in various
series and parallel combinations. Our DirectSOFT 5 software is a similar program. It uses
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graphic symbols to develop a program; therefore, you don't necessarily have to know the
instruction mnemonics in order to develop your program. However, knowledge of mnemonics
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will be helpful, whenever it becomes necessary to troubleshoot a program using a handheld
programmer (HPP).
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Many of the instructions in this chapter are not program instructions used in DirectSOFT
5, but are implied. In other words, they are not actually keyboard commands, however, they
can be seen in a Mnemonic View of the program once the DirectSOFT 5 program has been
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developed and accepted (compiled). Each instruction listed in this chapter will have a small
chart to indicate how the instruction is used with DirectSOFT 5 and the HPP.
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The following paragraphs show how these instructions are used to build simple ladder programs.

END Statement

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All DL05 programs require an END statement as the last instruction. This tells the CPU that
this is the end of the program. Normally, any instructions placed after the END statement will
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not be executed. There are exceptions to this such as interrupt routines, etc.. This chapter will
discuss the instruction set in detail.
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Simple Rungs

a A
You use a contact to start rungs that contain both contacts and coils. The boolean instruction
that does this is called a Store or, STR instruction. The output point is represented by the
Output or, OUT instruction. The following example shows how to enter a single contact and
b B
a single output coil.
C c
D D
5-4 DL05 Micro PLC User Manual, 6th Edition, Rev. D
DS5 Implied
HPP
X0
All programs must have
an END statement
DirectSOFT5
DirectSOFT Example
X0
Used
Y0
OUT
END
Y0
OUT
END
Handheld Mnemonics
STR X0
OUT Y0
END