ABB Instrumentation
Limit switches from ABB serve the essential purpose of determining when machinery components move to a designated position and reliably signal that event to the machine's control system. This is a key application where ABB products and their associated technologies are widely used, and for good reason. Limit switches command respect in the industrial world not only because of their basic function but also because they embody key industrial principles: reliability, ruggedness, maintainability, adaptability, and (last but not least) safety.
ABB limit switches come in a range of configurations and are installed in a variety of ways, and they are made of or housed in materials that can take the kinds of abuse one sees in the field, from nearly any kind of industrial process. In fact, it hardly seems an exaggeration to say that if a limit switch can survive in an industrial situation, an ABB limit switch can. ABB's limit switches are clearly designed for modern automation. They provide a number of advanced connectivity options, even integrating with fieldbus and digital systems in some models, which allow operators to do what most industries really want to do: work smarter and more efficiently.
FAQs
What are ABB limit switches used for?
ABB limit switches are used for position detection, safety interlocks, and motion control in industrial machinery and automation systems.
What types of ABB limit switches are available?
ABB offers roller lever, plunger, rod lever, adjustable head, and various modular switch designs to match different mechanical movements.
Do ABB limit switches support safety applications?
Yes. Many models include positive-opening contacts, making them suitable for safety interlocks, emergency stops, and protective systems.
What industries use ABB limit switches?
They are commonly used in manufacturing, material handling, robotics, packaging, conveyor systems, and process automation.
Can ABB limit switches be used in harsh environments?
Many models feature high ingress protection (IP) ratings, corrosion-resistant materials, and rugged housings suitable for harsh conditions.
Analog and Digital Control Signals: The Basics
Digital Signals
Digital signals are represented in either a true or false. There is no gray area with digital signals. An example of this might be a light switch. A light switch is either on or off. Another example of this might be a motor that is running or not running. Digital signals can be generated with both AC and DC circuits with varying voltages, currents and resistance. Some practical examples of using digital signals in an industrial environment might be if a pump is running or not running or a whether a valve is open or closed.
Analog Signals
Analog signals convey information in the form of a range. A light switch might be on or off as a digital signal, but a dimmer switch would be an analog signal. It can be on or off, but it can also be somewhere in between. A practical example of using analog signals in an industrial environment would be if there is a need to measure the level of a tank; whether it's full, empty or somewhere in between. Analog signals can take many different forms with some of the more common being a 4 to 20 milliamp signal or a 0 to 5 or 0 to 10 volt signal.
Communication
Communication in a device can either be sent or received. Whether that data is sent or received depends on the type of information. Is there a need to monitor the status of something? If so, an input needs to be received about that information. Is there a need to control something? If so, an output needs to be sent about what needs to occur. Receiving inputs and setting outputs are both things that can be accomplished by using both digital and analog signal types. Therefore, the signals are referred to as analog outputs (AO), analog inputs (AI), digital inputs (DI) or digital outputs (DO).