Safety relays are a special type of relay you can use to build a safety circuit. Safety is a critical issue in machine design. It is crucial to have a good basic understanding of the principles behind safety relays and safety circuits.
With that said, safety often becomes a confusing matter because a lot of terminology is attached to it. All that terminology comes from the standards describing safety circuits, functional safety and thereby safety relays.
You probably have heard about the Siemens S7-1200 PLC. It is the latest Siemens PLC and the best for learning. Get the Starter Kit with the programming software SIMATIC S7 TIA Portal and begin learning Siemens PLC programming. You can even control the S7-1200 PLC with your smart phone!
You may know the difference between normally open and normally closed contacts, but do you know where to use them? This article will teach you where to use normally open and where to use normally closed for inputs and in your PLC program. You will learn how to connect your PLC program with the physical PLC inputs.
Ladder logic symbols are the basic building blocks for ladder diagrams. Right here you will find all the ladder diagram symbols which are described in IEC 61131-3. The symbols are available for download in all formats and in a PDF-file.
This is an introduction to PLC logic. You can use PLC logic to build PLC programs with simple electrical circuit diagrams. In this article, I will use combinatorial logic to build the functionality of a PLC program.
And to get as close as possible to real a PLC programming language like ladder logic, the PLC logic in this article will be contacts and relays in an electrical circuit.