3. input and output tests - Sort line by length



Welcome to today's lesson, where we will explore a key step often overlooked by developers - testing. This is not only a challenge for beginners, but also for experienced code developers. Why stop at the testing stage? Because before we start writing complex program code, we need to make sure our input and output signals work as expected.

I invite you to delve into the content of the task, where you will learn how to effectively test all input and output signals. Don't be one of those programmers who forgets this important step. In the lesson, I'll show you how to run tests quickly and effectively so you can make sure your code works as expected.

Video 1

Table of contents

00:50 Content of task
01:25 Tests of input/output signals
01:52 Conclusion

Video 2

Validity of the Test Stage in PLC Programming

Welcome! Today we are going to focus on one of the important steps in PLC programming that is often overlooked, both by novice programmers and more experienced ones. It is about the process of testing the code, especially the input and output signals.

Why are Tests Crucial?

In the programming world, we mainly focus on creating effective programme code, but we forget a key stage - testing. Why is this important? Because before we start writing programme code, we need to make sure we have a solid foundation for signal testing.

Step by Step - How to Perform Tests?

  1. Preparation of Programme Code: Before we start testing, we need to have the programme code ready. This includes, in particular, the main block (Main) and the auxiliary functions and blocks.
  2. Uploading the Code to the Controller: Next, let's upload our programme code to the controller. Make the code properly integrated with the main block and other functions.
  3. Testing on an Empty Block: Create an empty block to carry out the tests. Ensure that all input and output signals are correctly configured.

Focused on Signal Tests

It is important to focus on testing all input and output signals. This is a key aspect of PLC programming. Test each signal, making sure it responds as expected.

I invite you to look at an earlier lesson where signal testing is discussed in detail. This is an essential part of PLC programming, especially if you are starting out.


  • An important stage often overlooked by developers is the testing stage.
  • Testing the programme code before writing it is important.
  • Programmers, whether beginners or advanced, should focus on testing input and output signals.
  • Before testing the programme code, it is a good idea to prepare a suitable test environment on your desk.
  • It is worth testing all input and output signals of the programme code.
  • The testing process involves calling a function, deleting, and uploading the programme code to the controller.
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Author of entries
Tomasz Gilewski

Hello, my name is Tomasz Gilewski. I am the author of books on the S7-1200 controller and HMI panels (i.e. Siemens hardware). I have been programming exclusively on Siemens hardware and engineering tools for several years.

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