In this tips and tricks post I will demonstrate the usage of the attribute: ‘instance-path’. The instance path attribute allows you to get the instance path of the containing POU in a string variable. Something I find particularly useful for error-logs and debug messages. How to use it 1. We need a string variable which […]
During the latest COVID lock down, scrolling randomly through the internet, I stumbled on Project Euler, a series of mathematical/computer programming problems. So I thought it would be fun to try a few challenges with Structured Text. After completing the first 2 challenges it occurred to me that it might be fun to publish a repo on Github with this project, to see if I can get more people to solve challenges and on the fly creating a lot of mathematical Structured Text example code.
RPC method are methods in TwinCAT which can called from outside the scope of your application. For example an OPC UA client or an ADS client. In this post I show how to invoke RPC methods in your TwinCAT PLC from a .NET application.
A popular programming design in high level languages as C# is the so-called ‘fluent code’ or ‘fluent interface’. But what is a fluent interface and how can we implement this in Structured Text? In this post I briefly explain what a fluent interface is and give an example of a fluent interface in Structured Text.
It was already available in CODESYS, but with the release of TwinCAT 4024 it’s now available in TwinCAT as well: the ABSTRACT keyword. Abstraction and the use of the abstract keyword is common practice in OOP and many higher level languages as C# support this. It’s often considered as the fourth pillar of OOP. In this post i’ll explain how to use the ABSTRACT keyword in TwinCAT with some practical examples.
In the post ‘How to use monitoring attributes’ I showed how to use the monitoring attributes: attribute ‘monitoring’ := ‘variable’ and attribute ‘monitoring’ := ‘call’. With these pragma attributes we can monitor and modify our function blocks properties. This comes however with a small drawback. As the online view now shows your properties and their backing fields your online view gets less clear. In this post I will show how to solve this with the hiding attributes.
Every programmer spends a considerable amount of time debugging their software. In the world of PLC programming it’s common to login to the PLC and monitor and write your variables. However, with the introduction of properties for your function blocks monitoring is not as plain as it used to be. In this post I’ll explain how to use monitoring attributes for your properties in TwinCAT.
Every year I participate in a number of online code challenges like Facebook Hacker Cup, Google Code Jam and Advent of Code. Although I never make it really far I quite enjoy the puzzles which I usually make in C#. Definitely not the fastest language out there, but LINQ makes life easy 🙂 . Since I spent every week a considerable amount of time PLC programming, I found myself wondering if I could solve A Code Jam challenge with Structured Text. Spoiler alert, yes you can, but it doesn’t come very easy.. So I decided to write a small post about it, pointing out the challenges I faced.