Software for Education and Industry

PLC Easy Learner


Allen-Bradley RSLogix® Micro


Tired of wading through mounds of technical manuals or myriads of websites to learn how to program a PLC? This program shows you step-by-step how to program an Allen-Bradley Micrologix® PLC using free Allen-Bradley's RSLogix® Micro Starter Lite software.

Simply download the free Allen-Bradley RSLogix® Micro Starter Lite software from Rockwell Automation then follow the exercises in this program to learn how to program PLCs using Allen-Bradley's RSLogix® software. Exact instructions on how to download RSLogix®  Micro Starter Lite software are included in the program. You do not need an actual PLC to use this program.

This program is written in everyday, easy to understand language and tells you what you need to know when you need to know it.  It is written in .html format so you can use your favorite internet browser with hyperlinks, bookmarks, and word searches, and requires no software installation on your computer.  Just double click on the Table of Contents.html and your internet browser launches the program.

This program explains every Micrologix 1000 instruction and shows you:

This program is written by a Professional Engineer with 14 years industrial experience and 20 years experience teaching electrical engineering technology at the college level.

PLC Easy Learner Table
      of Contents

Sample Exercise


 Chapter 14.  File Shift/Sequencer Instructions


Step 3) - Add a switch and a BSR  instruction

BSR (Bit Shift Right) is an output instruction that shifts a data word one bit to the right each time the instruction is energized.  It is useful for tracking parts down an assembly line, for instance, where each bit represents a part.

Add a switch and a BSR instruction to a new rung as shown below.  The BSR  instruction is in the File Shift /Sequencer category of instructions as shown circled in red.  Enter N7:1 for the File, R6:1 for the Control, I:0/3 for the Bit Address, and 5 for the Length of the BSR  instruction.  

Append another rung and add a normally open contact with address R6:1.UL in series with an output O:0/1. 

Your screen should look like the following:

After a BSR instruction has been added

When the program is run, each time I:0/2 is closed the following will happen:


1) bit 0 of N7:1 will be sent to bit 10 of word R6:1, which is also called R6:1.UL

2) all the bits of word N7:1 will be shifted one position to the right, and 

3) the status of Bit Address I:0/3 will be brought into bit 4 of word N7:1. 


This operation is shown graphically below:

If a number greater than 16 is entered for the Length of the instruction, the shift will occur across word boundaries, but R6:X.UL will always be energized by the least significant bit of the word entered as the File parameter. 

Assuming N7:1 initially contained all zeros, the following screen shot shows the N7:1 word after switch I:0/2 has been closed 5 times with switch I:0/3 closed each time. On the next closure of switch I:0/2, the 1 from bit 0 of word N7:1 will be sent to R6:1.UL, turning on output O:0/0.

N7:1 word after switch I:0/2 has been closed 5 times with I:0/3 closed

Hardware/Software Requirements:

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