Unleashing the Power of Indirect Addressing in PLC Programming

Name: Unleashing the Power of Indirect Addressing in PLC Programming
Uploaded: 2024-06-24T09:10:29+00:00
Duration: 2 min 52 s

accautomation.ca

What is the most powerful PLC instruction? What instruction or concept is the most powerful when programming any manufacturer's PLCs? Many people will guess timers, counters, or the set and reset bit instructions. These are all great instructions, but indirect or pointer instruction is the most powerful.
In PLC programming, pointers, also called indirect addressing, store or retrieve memory addresses of data or instructions. They are instrumental when dealing with large amounts of data or performing complex calculations. Machine recipes, sequence control, and test result storage are just a few examples of where this powerful PLC instruction is used.
We will examine how indirect addressing works in the Click, Do-More, and Productivity PLCs. You will discover how easily and powerful pointers are when programming. Let's get started.
Detailed information and links can be found in the corresponding post here.
https://accautomation.ca/the-most-powerful-plc-instruction/
PLC Beginner’s Guide to PLC Programming
https://accautomation.ca/programming/plc-beginners-guide/
Here are the controllers that we have covered at ACC Automation:
BRX Do-More Series (Do-More Designer Software + Simulator)
https://accautomation.ca/series/brx-do-more-plc/
Productivity Series
https://accautomation.ca/series/productivity-1000-plc/
https://accautomation.ca/series/productivity-2000-series-plc-p2000/
Click PLC Series
https://accautomation.ca/series/click-plc/
Omron CP1H Series
https://accautomation.ca/series/omron-plc-cp1h-series/

View Transcript

0:00

What is the most powerful PLC instruction

0:02

You might think it's timers, counters, or set and reset bit instructions

0:07

But today, we're exploring indirect or pointer instructions, arguably the most powerful tool in PLC programming

0:15

Indirect addressing, also known as pointer instructions, allows you to store or retrieve memory addresses of data or instructions

0:23

This is incredibly useful when dealing with large amounts of data or performing complex calculations

0:30

Imagine you're managing machine recipes, sequence control, or storing test results. Indirect addressing can handle all of these tasks efficiently

0:39

Let's see how this works in CLICK, DoMore, and Productivity PLCs. In CLICK PLCs, indirect addressing is referred to as pointer addressing

0:49

It uses DS registers as the offset value and can be applied to various data register memory types like DS, DD, DF, and more

0:59

For instance, DD DS3 points to the address in DD that the DS3 value contains

1:05

If DS3 has a value of 145, the address will use DD 145

1:12

As DS3 changes, the corresponding DD address changes too, allowing you to log or retrieve values dynamically

1:20

In Productivity PLCs, we use arrays for indirect addressing. A tag name can be specified as the index of the array

1:28

making it easy to manage complex data structures. For example, widget progress pointer could be a one-dimensional array

1:35

while widget progress pointer row, pointer column, could be a two-dimensional array

1:40

Individual elements are addressed by their index, making data manipulation straightforward. In DoMore PLCs, indirect addressing allows an instruction's memory address to vary during runtime

1:53

pointing to multiple locations. All data blocks in the CPU can be used as arrays

1:59

For example, using V0 as the pointer in an array with values ranging from 1 to 6

2:03

the instruction move VV0 to V100 dynamically changes the data location based on V0's value

2:10

Indirect addressing, or pointer instructions, are the most powerful tools in PLC programming

2:16

They offer unparalleled flexibility, allowing you to handle large datasets, perform complex calculations, and easily troubleshoot your systems

2:25

Whether you're using CLICK, DoMore, or Productivity PLCs, indirect addressing can streamline your programming process

2:33

From machine recipes to sequence control and test result storage, the applications are endless

2:39

How many more examples and applications can you think of using indirect pointers

2:44

Let us know in the comments below. Thanks for watching and see you next time

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Unleashing the Power of Indirect Addressing in PLC Programming