Building a PLC Program – Part 5 – Simon Game

We will now look at the Game of Simon for our part 5 in this series of building a PLC program. Learning all about bit manipulation and sequencers Simon is a memory game introduced in 1978. It has four colored buttons, each producing a particular tone when it is pressed or activated by the device. … Read more

Create a PLC HMI Training Learning Environment

We will now create a PLC with HMI Training and learning environment. We will use the Automation Direct Do-More programming software tied into the Advanced HMI learning package via Modbus TCP. All of the software is free and fully functional. Learn PLC programming and use a powerful HMI (Human Machine Interface) easily and freely. Setting … Read more

Excel Secrets: Implementing Modbus TCP Protocol with VBA!

We are using Modbus TCP protocol, reading ten registers in the PLC, and displaying a bar graph in Excel. e will use Visual Basic for Applications (VBA) to communicate with a PLC. Previously we have used VB6 to communicate Modbus TCP. Sequence for Modbus TCP on Excel using VBA The following steps will be done: … Read more

Three Free PLC Programming Software Tools

Three Free PLC Programming Software Tools

Manufacturers have software to program the programmable logic controller (PLC) or the human-machine interface (HMI). However, there are a few free tools that will help in the development of your PLC programs. We will look at three software tools and show how beneficial they can be to you. Free PLC Software Tools Synergy – Share … Read more

How to Send Email to SMTP Server (VB6)

Simple mail transfer protocol (SMTP) is the email protocol for sending information. We can use this ability to email from our data logged from the PLC. Faults or errors the PLC detects can be emailed to individuals for correction. Shift reports on productivity can be automatically emailed to recipients. Note: Google is removing “Less Secured … Read more

Building a PLC Program Part 3 – Traffic Light

In part 1, we looked at writing PLC programs to control a traffic light using discrete bits and timed sequencing using indirect addressing. Part 2 used indirect addressing for inputs and output to control the program’s sequence of pneumatic (air) cylinders. We will now return to the traffic light application and expand our program significantly. … Read more

How PLC Outputs Work – Discrete and Analog

This post is a further follow-up from my original ‘Here’s a Quick Way to Understand PLC Inputs and Outputs.’ There are two different kinds of PLC outputs, Discrete and analog. Discrete outputs are either ‘ON’ or ‘OFF’; 1 or 0. You can think of them as a single light bulb. Analog outputs have a range … Read more

How PLC Inputs Work – Discrete and Analog

This post is a further follow-up from my original ‘Here’s a Quick Way to Understand PLC Inputs and Outputs.’ There are two different kinds of PLC inputs, Discrete and analog. Discrete inputs are either ‘ON’ or ‘OFF’; 1 or 0. You can think of them as a single switch. Analog inputs have a range to … Read more

How to Implement Omron PLC Host Link Protocol

The hostlink communication protocol is a method developed by Omron for communication to PLCs and other equipment. This ASCII-based protocol is used over RS232 or RS422/RS485. It is a many-to-one implementation, meaning you can communicate with up to 32 devices back to a master. (1: N) This communication on the industrial floor can control PLCs, Temperature … Read more

Here is a Method for a Faster PLC Program

PLC programming involves both direct and indirect addressing. Direct address programming involves writing each ladder logic rung to do the operation required. We often forget about using powerful indirect addressing to solve our logic. Indirect Addressing – Faster PLC Program The below-animated picture will show a simple example of using indirect addressing. This will use … Read more