Category Archives: PLC

PLC Programming Example – Palletizer

We will apply the five steps to PLC program development to a palletizer example. Our example will allow you to determine how many layers of boxes you want on each skid.

Developing the PLC program is a process that can be clearly defined. In our series on the five steps to PLC program development we have done some similar practical examples.
PLC Programming Examples – Five Steps to PLC Program Development
– Press
Process Mixer
Shift Register (Conveyor Reject)
Paint Spraying
Delay Starting of 7 Motors
– Pick and Place
– Sorting Station (Shift Register)

Define the task: (1)
Watch the sequence of operation video below. This will demonstrate the pallet layer selection, running and resetting of the machine.
Watch on YouTube : PLC Programming Example – Palletizer Testing
Continue Reading!

BRX PLC Math Instructions

Math instructions are used to perform mathematical calculations. The BRX PLC has math instructions that can be used in a wide variety of applications. We will be looking at the INC increment, DEC decrement, LERP linear Interpolation, RANDSEED Random Number Seed and the MATH Calculated Expression instructions. Your automation system that you implement may involve some or all of these instructions. As a system integrator you will require the use of these instructions in your commissioned programs.
Let’s get started with the BRX PLC Math Instructions. Continue Reading!

BRX PLC Compare Instructions

Compare instruction are often used in PLC programs to test pairs of values. The output of this comparison conditions the logical continuity of a rung. The BRX series of programmable logic controllers 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)
Besides these instruction the BRX PLC will also have compare instructions for the built in real time clock of the system. We will be looking at these instructions along with some programming examples. As a system integrator, this ability can prove very useful to you in the field when commissioning your automation system.
Lets get started with the BRX PLC Compare Instructions. Continue Reading!

PLC Programming Example – Sorting Station (Shift Register)

We will apply the five steps to PLC program development to a sorting station example. The program will use shift registers to track coloured parts down a conveyor and sort depending on colour into one of three locations.

Developing the PLC program is a process that can be clearly defined. In our series on the five steps to PLC program development we have done some similar practical examples.
Five Steps to PLC Program Development
– Press
Process Mixer
Shift Register (Conveyor Reject)
Paint Spraying
Delay Starting of 7 Motors
– Pick and Place

Define the task: (1)
Watch the sequence of operation video below.
Watch on YouTube : PLC Programming Example – Sorting Station Testing
Continue Reading!

Modbus RTU BRX PLC Master to Click PLC Slave Communication

Recently I was asked to demonstrate communication between a BRX PLC and Click PLC using Modbus RTU. Both PLCs are available from automation direct com. Modbus serial communication (Modbus RTU) is a standard protocol used in many automation devices. It works on a Master / Slave configuration. You can have only one master per network on Modbus RTU (Remote Terminal Unit). A maximum of 32 devices (Nodes) on the network can communicate to the master. A review of the Modbus RTU protocol (RTU frames) can be seen at the following URL.
http://www.rtaautomation.com/technologies/modbus-rtu/
Using the BRX PLC as a Master, we will be communicating to the Click PLC (Slave). Our example will read 10 registers from the Click PLC and write 10 registers from the BRX PLC. Let’s get started! Continue Reading!

BRX PLC High Speed IO

The BRX series of programmable logic controllers has built in high speed inputs and outputs. Every CPU will have either 6 or 10 high speed inputs (HSI) available depending on the model. These inputs can be used for input frequencies from 0 to 250Khz. 250Khz represents 250000 input counts per second that can be coming from devices connected to your PLC like an encoder. Every BRX CPU unit also has 2, 4 or 8 high speed outputs (HSO) available depending on the model. The outputs can send a frequency of pulses out up to 250Khz. Due to the speed of the IO, these functions available on the BRX PLC will operate asynchronous with the PLC scan time.
We will be looking at sending an output of pulses at different frequencies from our BRX PLC and inputting these back into the high speed inputs of the PLC. So our output will be wired back into our input. We will then display the frequency of the input pulses and the count. As a system integrator, this ability to send and receive high speed inputs and outputs can prove very useful to you in the field when commissioning your automation system.
Let’s get started with the BRX PLC High Speed IO. Continue Reading!

BRX PLC Counters

A majority of the programmable logic controller (PLC) programs will include a counter instruction. The BRX series of programmable logic controllers have several different counters available for your program. There are five different basic counter instructions in the PLC. The memory area for counters (CT), include the Counter PVs (Present Values) Counter SVs (Set Values) and the Counter Completion Flags. The default size of the counter area is CT0 – CT255. This size can change to the amount that we need for our program. Please see BRX PLC Numbering Systems and Addressing on how to change the memory configuration of the controller.
We will be looking at the counter instructions in the BRX PLC along with some programming examples. As a system integrator, this ability can prove very useful to you in the field when commissioning your automation system. When dealing with counters, we need to look at timing charts. The Secret of Using Counters is a good refresher on using timing charts.
Let’s get started with the BRX PLC Counters. Continue Reading!

BRX PLC Timers

A majority of the programmable logic controller (PLC) programs will include a timer instruction. The BRX series of programmable logic controllers have several different timers available for your program. There are nine different basic timing instructions in the PLC. The memory area for timers, include the Timer PVs (Present Values) Timer SVs (Set Values) and the Timer Completion Flags. The default size of the timer area is T0 – T255. This size can change to the amount that we need for our program. Please see BRX PLC Numbering Systems and Addressing on how to change the memory configuration of the controller.
We will be looking at the timer instructions in the BRX PLC along with some programming examples. As a system integrator, this ability can prove very useful to you in the field when commissioning your automation system. When dealing with timers, we need to look at timing charts. The Secret of Using Timers is a good refresher on using timing charts.
Let’s get started with the BRX PLC Timers. Continue Reading!

PLC Programming Example – Pick and Place

We will apply the five steps to PLC program development to a pick and place robot example. The example will use a BRX PLC communicating to Factory IO (3D Software Simulator). Developing the PLC program is a process that can be clearly defined. In our series on the five steps to PLC program development we have done some similar practical examples.
Five Steps to PLC Program Development – Press
PLC Programming Examples:
Process Mixer
Shift Register (Conveyor Reject)
Paint Spraying
Delay Starting of 7 Motors

Define the task: (1)
Watch the sequence of operation video below.
Watch on YouTube : PLC Programming Example – Pick and Place Testing
Continue Reading!

BRX PLC Online Editing and Debug Mode

Our first program for the BRX PLC involved a start stop jog circuit. We will now use the Do-More Designer Software to modify this program while the PLC is scanning the logic. This is referred to as online programming or online editing. As a system integrator, this ability can prove very useful to you in the field when commissioning your automation system.
We will also be using the special Debug Mode of the software to monitor the ladder logic status and bits on a scan by scan basis. Forcing the inputs and outputs, we will control the execution of the PLC scan. This is a great feature of the Do-More Designer software.
Here is a link explaining the logic behind our circuit.
How to Make a Start Stop Jog Circuit in a PLC
Let’s get started. Continue Reading!