Tag Archives: plc troubleshooting

Click PLC Simple Conveyor EasyPLC


The Machine Simulator (MS) is part of the EasyPLC software suite. It has many built-in machines that can be programmed. A simple conveyor is one of these machines. This is usually the starting point for learning about the machine simulator. This conveyor example will use two digital inputs and two digital outputs. A pallet will move back and forth on the conveyor. When the pallet is detected on each end it will stop and reverse direction. If both motors are started at the same time, the motors will burn up. This will be demonstrated. The machine simulator will allow you as the programmer to make mistakes before trying your program in the physical world.
Click PLC Simple Conveyor EasyPLC
The Click PLC will be used to program this virtual machine. Using the Click Plus PLC, we will connect the simulator to the simple conveyor machine. This will be done using Modbus TCP (Ethernet) for communications. Using the five steps for program development we will show how this is programmed. Let’s get started. Keep on Reading!

ACC Automation 2017 Review

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We would like to take a few minutes and reflect on the past, current and future of ACC Automation. 2017 has been our best year yet thanks to you. Your questions, comments and suggestions have helped us to build the site that you see today.
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Three Free PLC Programming Software Tools

Every manufacturer has there own software to program the programmable logic controller (PLC) or the human-machine interface (HMI). However, there are a few tools that are free which will help in the development of your PLC programs. We will look at three of these software tools and show how beneficial they can be to you.


Free PLC Software Tools
Synergy – Share Multiple Computer Systems

When programming, I usually will have my laptop for the ladder logic and my desktop for the screen software. Connecting the two together and using one mouse and keyboard saves me the aggravation of switching back and forth between the keyboards.
Synergy - Three Free PLC Programming Software Tools

Synergy lets you easily share a single mouse and keyboard between multiple computers with different operating systems each with its own display without special hardware. It is intended for users with multiple computers on their desk since each system uses its own monitor(s). Redirecting the mouse and keyboard is as simple as moving the mouse off the edge of your screen. Synergy also merges the clipboards of all the systems into one, allowing cut-and-paste between systems. It works on Windows, Mac OS X, and Linux.

Synergy Website
http://synergy-project.org/
Downloads:
Synergy for Windows:
http://download.cnet.com/Synergy/3000-2072_4-10714570.html
Synergy for Mac
http://download.cnet.com/Synergy/3000-2094_4-75362427.html

Windows Calculator – Free PLC Software Tool

That’s right. The windows calculator can be a very helpful tool when it comes to programming PLCs. When you need to convert, hexadecimal to binary, BCD to hexadecimal or any other combination the windows calculator can do it for you.

What everybody ought to know about PLC numbering systems.

Start the calculator. Start – All Programs – Accessories – Calculator
Calculator - Three Free PLC Programming Software Tools

View the programmer calculator. View – Programmer (Alt + 3)
Calculator 02 Programmer

We can then choose Hex for our numbering system. Then Word for our length of the address. You will notice that the display will show the Bin equivalent along with the marking of bit 0 to bit 15.
Calculator - Three Free PLC Programming Software Tools

7ABC base 16 = 0111 1010 1011 1100 base 2 = 31420 BCD
Calculator - Three Free PLC Programming Software Tools

Note: I am using Windows 7, but all of the versions of window calculator have similar functionality.

Windows HyperTerminal – Free PLC Software Tool

Serial communication can be difficult using PLC. HyperTerminal can be used to monitor the communication being sent from or to the programmable logic controller. Just hook up to the serial port and program HyperTerminal to monitor the port. Set the correct Data Bits, Baud Rate, Parity, Stop Bits, etc. Viewing the information on the monitor will assist you in seeing the exact data being sent to, or received by the PLC.
HyperTerminal - Three Free PLC Programming Software Tools

HOW TO IMPLEMENT THE OMRON PLC HOST LINK PROTOCOL

Hype Terminal – Windows 7 and 8

HyperTerminal was no longer sent with windows when Windows 7 was introduced.

Hype Terminal is fully functional replacement of HyperTerminal, perfect for GSM and GPS debugging, works with AT Commands. You can use Hype Terminal to help debug source code from a remote terminal. You can also use Hype Terminal to communicate with older character-based computers. Hype Terminal is designed to be an easy-to-use tool and is not meant to replace other full-feature tools available on the market.
Three Free PLC Programming Software Tools

Download Hype Terminal:
http://download.cnet.com/Hype-Terminal/3000-2086_4-76158601.html

Watch on YouTube: Three Free PLC Programming Software Tools
If you have any questions or need further information please contact me.
Thank you,
Garry



If you’re like most of my readers, you’re committed to learning about technology. Numbering systems used in PLC’s are not difficult to learn and understand. We will walk through the numbering systems used in PLCs. This includes Bits, Decimal, Hexadecimal, ASCII and Floating Point.

To get this free article, subscribe to my free email newsletter.


Use the information to inform other people how numbering systems work. Sign up now.

The ‘Robust Data Logging for Free’ eBook is also available as a free download. The link is included when you subscribe to ACC Automation.


PLC Programming Example – Process Mixer

We will apply the five steps to PLC Program development to our next programming example of a process mixer.
The process mixer will be programmed using ladder logic. We will discuss each step of the PLC program development.

1 – Define the task:
How does the process mixer work?

PLC Prgramming Example - Process Mixer



A normally open start and normally closed stop pushbuttons are used to start and stop the process. When the start button is pressed, solenoid A energizes to start filling the tank. As the tank fills, the empty level sensor switch closes. When the tank is full, the full-level sensor switch closes. Solenoid A is de-energized. The mixer motor starts and runs for 3 minutes to mix the liquid.  When the agitate motor stops, solenoid B is energized to empty the tank. When the tank is completely empty, the empty sensor switch opens to de-energize solenoid B. The start button is pressed to repeat the sequence.

2 – Define the Inputs and Outputs:
What sensors will be used in the PLC program?

Inputs:
Start Pushbutton – Normally Open – On/Off
Stop Pushbutton – Normally Closed – On/Off
Empty Sensor Switch – On/Off
Full Sensor Switch – On/Off
Timer 3 minutes done bit – On/Off (Internal)

Outputs:
Mixer Motor – On/Off
Solenoid A – Fill – On/Off
Solenoid B – Empty – On/Off
Timer 3 minutes – (Internal)

3 – Develop a logical sequence of operation:
How the PLC example program is to solve the logic.

A flow chart or sequence table is used to fully understand the process.  It will also prompt questions like the following.

What happens when electrical power and/or pneumatic air is lost? What happens when the input / output devices fail? Do we need redundancy?

This is the step where you can save yourself a lot of work by understanding everything about the operation. It will help prevent you from continuously re-writing the PLC logic. Knowing all of these answers upfront is vital in the development of the PLC program.

Process Mixer - Sequence Table

4 – Develop the PLC program
Writing the PLC sample ladder logic program for the process mixer.

Since we need to continue the sequence when the power goes off then memory retentive locations in the PLC must be used. In our example, we will use the ‘V Memory’ locations.

The first thing in our program is to control the start and stop functions. This is done through a latching circuit. From the sequence table, we know that to reset the sequence we need to have the timer done and the empty sensor off.Process Mixer Program 1

The filling of the tank is done through Solenoid A. It is turned on by the start signal and off by the full sensor switch. (Sequence Table) You will notice that we have a memory retentive output and the actual output to active the solenoid.Process Mixer Program 2

The memory retentive timer will start timing when we have the start sequence signal and when the empty and fill sensors are on. The timer will reset when the empty and fill sensors are off. Mixing motor will be on when the timer is timing and when the timer is not done.Process Mixer Program 3

Solenoid B turns on to empty the tank when the timer is done and the full and empty sensors are on. It will reset when the empty sensor switch goes off.Process Mixer Program 4

5- Test the program
Simulate the PLC program of the Process Mixer

 

PLC Programming Example - Process Mixer

Test the program under many conditions. Check to see what happens when power is removed.

Using this five-step to program development technique will shorten your programming time. The result will be a better-defined logic and easier to understand the program, because it has within the documentation the logic flow chart or sequence table.

Watch on YouTube: PLC Programming Example – Process Mixer

Factory IO provides a 3D simulation of the process. Testing of the program is important and should be done in a variety of ways. Factory IO provides a straight forward method of seeing your program in action before you wire your application.

We will be using the BRX PLC Modbus TCP Server (Slave). Factory IO will be the Modbus TCP Client (Master). When the tank fills up we will start a dwell time instead of the mixer time for the simulation.
Here is the mapping of the inputs and outputs using Factory IO.

Factory IO Website is at the following URL:
https://factoryio.com/
Documentation is well done. Start at the ‘Getting Started’ at the following URL:
https://factoryio.com/docs/

You can download the PLC program and Factory IO scene here.

Watch the following video to see this simulation in action.

Watch on YouTube: Process Mixer Test Simulation
If you have any questions or need further information please contact me.
Thank you,
Garry



If you’re like most of my readers, you’re committed to learning about technology. Numbering systems used in PLC’s are not difficult to learn and understand. We will walk through the numbering systems used in PLCs. This includes Bits, Decimal, Hexadecimal, ASCII and Floating Point.

To get this free article, subscribe to my free email newsletter.


Use the information to inform other people how numbering systems work. Sign up now.

The ‘Robust Data Logging for Free’ eBook is also available as a free download. The link is included when you subscribe to ACC Automation.