Tag Archives: plc programming ladder logic

Productivity 1000 Series PLC Drum Sequencer Instructions

The productivity series of PLCs has a Drum and Sequencer instruction.
Drum instructions are great tools. They mimic an electromagnetically drum sequencer. Have you ever seen the mechanisms of a music box? Ok so it’s a little drum with pegs that catch and flick the chimes in a particular sequence to play whatever tune is on the drum. So in the PLC you can have a drum driven by an event, (input from a limit switch or button), or by time.

Sequencers are similar to the drum instruction. The sequencer output can have up to 16 Boolean, Integer or Numerical Tags per step. Drum instruction outputs are limited to the same 16 bit (Boolean) outputs. Each step in the sequencer can be defined by time or /and event and specified outputs can be set going into and out of the step.
We have done similar Drum instructions for the BRX Series PLC and the Click PLC.
BRX PLC Drum InstructionVideo
Click PLC Drum InstructionVideo
We will be discussing the drum and sequencer instructions in the Productivity Series PLC. Simple examples will be done to demonstrate the power of these instructions. Let’s get started. Continue Reading!

PLC Fiddle Shift Register Challenge

Shift registers will move (shift) bits in a word (register) to the left or right.

If we look at an example of boxes moving along a conveyor belt, the boxes would represent the bits in the register. The movement of the conveyor would be the shifting of the register that represents the movement of the boxes.

Shift registers are a form of sequential logic, which involves the present inputs and the prior history. All of the prior history is remembered.
We will be making a shift register in PLC Fiddle with the instructions provided. The output of the shift register will then be looked at for a reject area. Let’s get started. Continue Reading!

Productivity 1000 Series PLC Program Control

The program control method and instructions will allow us to specify what parts of the logic get solved and when this happens. This will control how the PLC will scan and solve your logic in your program using a synchronous PLC Scan. Understanding the PLC program scan will explain the synchronous and asynchronous program scanning.
Individual ladder logic programs get solved left to right, top to bottom. The result of the rung before is available for the next rung. The Task Management provides a method to clearly see the overall flow of your PLC program. Looking into the folders of the task management we can see blocks of code. These blocks of contain the ladder logic that will solve our logic. Instructions within the ladder logic code can also determine how the PLC will solve the logic.

We will be looking at using program control in the Productivity 1000 Series PLC.
Let’s get started. Continue Reading!

PLC Fiddle Compare Challenge

Just about every program usually has some data comparison instruction. This is the ability to compare information from one area of the controller to another and act on results. The output of this comparison conditions the logical continuity of a rung. PLC Fiddle is a free online browser simulator and has the following compare contact instructions.
= (if Equal contact)
<> (if Not Equal contact)
> (if Greater Than contact)
>= (if Greater Than or Equal contact)
< (if Less Than contact)
<= (if Less Than or Equal contact)
We will be looking at these instructions along with some programming challenges. As a system integrator, this ability can prove very useful to you in the field when commissioning your automation system. We will look at these compare instructions and show the parameters required to program them. Our compare challenges will help you gain a good understanding of how we can use compare in the PLC. Trying these challenges with PLC Fiddle is fun and will help you with PLC programming. Let’s get started. Continue Reading!

Productivity 1000 Series PLC Array Functions Part 3

An array is a storage area for a group of common data type tags. They usually have some relationship to each other and need to be manipulated as a group.

Previously we defined an array and use this in an indirect addressing program. It sequenced bits in an output card indirectly. We then looked at the following instructions: Array Statistics (STA), Copy Array (CPA), Fill Array (FLA) and Shift / Rotate Array (SRA). We will now look at the final four array instructions:
Pack Boolean Array (PBA) – Pack an Array of Boolean tags into a destination Word Array
Pack Word Array (PWA) – Convert one 8 bit or 16 bit array into a 16 or 32 bit Destination Array tag.
UnPack Boolean Array (UPBA) – Unpack an Array of Word tags into a destination Boolean Array.
UnPack Word Array (UPWA) – Convert one 32 or 16 bit array source tag into four 8 or 16 bit array tags.
Let’s get started with our final look at arrays in our Productivity 1000 Series PLC. Continue Reading!

PLC Fiddle Math Challenge

PLC programming will often involve math equations that need to be solved. Every manufacturer of programmable logic controllers will include math logic for you to use in your programs. Numbering systems play an important role. You can usually perform math using BCD (Binary Coded Decimal), Binary or Floating Point. Here is a link that will review the numbering systems in the PLC:
What everyone ought to know about PLC numbering systems

PLC Fiddles provides four basic BCD math and a move function for our circuits. Add, Subtract, Multiply Divide and Move. We will look at these math instructions and show you the parameters required to program them. Our math challenges will help you gain a good understanding of how we can use math in the PLC. Trying these challenges with PLC Fiddle is fun and will help you with PLC programming.
Let’s get started. Continue Reading!

Productivity 1000 Series PLC Array Functions Part 2

An array is a storage area for a group of common data type tags. They usually have some relationship to each other and need to be manipulated as a group.
Last time we defined an array and use this in an indirect addressing program. It sequenced bits in an output card indirectly. In this second part we will be looking at the following instructions:
Array Statistics (STA) – This will perform operations such as Summing, Averaging, Minimum Value and Median Value on an Array.
Copy Array (CPA) – Copy a block of 1 or 2 dimensional arrays into a destination array.
Fill Array (FLA) – Copy a value to a block of array elements
Shift / Rotate Array (SRA) – Concurrently Shift or Rotate values in an Array.
Let’s get started with the Productivity 1000 Series PLC arrays part 2. Continue Reading!

PLC Fiddle Counter Challenge

Counters are used in a lot of PLC programs that I have seen. A timing chart is the secret behind understanding of the counter that you need in your application. Making a timing chart before writing the program will ensure that all of the information will be accounted. The secret to using counters is a good review of using these timing charts.

PLC Fiddle has three different counter instructions for us to use in our programs. Count UP, Count Down and Reset. We will discuss the counter parameters and the three different instructions. Our counter challenges will help you gain a good understanding of how counters work in the PLC. Let’s get started. Continue Reading!

Productivity 1000 Series PLC Array Functions Part 1

An array is a storage area for a group of common data type tags. They usually have some relationship to each other and need to be manipulated as a group. We can use arrays for motion control, recipe management, sequencing (indirect addressing), math, etc. The Productivity 1000 Series PLC uses arrays which are programmed using the Productivity Suite Software.

We will be defining an array and use this in an indirect addressing program. This will sequence bits in an output card indirectly.
Let’s get started with the Productivity 1000 Series PLC arrays. Continue Reading!

PLC Fiddle Timer Challenge

Timers are present in just about every PLC program that I have seen. A timing chart is the secret behind understanding of the timer that you need in your application. Making a timing chart before writing the program will ensure that all of the information will be accounted. The secret to using timers is a good review of using these timing charts.

PLC Fiddle has three different timing instructions for us to use in our programs. On-Delay, Off-Delay and Retentive Timers. We will discuss the timer parameters and the three different instructions. Our timer challenges will help you gain a good understanding of how timers work in the PLC. Let’s get started. Continue Reading!