There isn’t a day in your life when you don’t use a limit switch at a residential facility or a commercial facility. It is an electromechanical device that is operated by applying physical force through an object. They are used to detect the presence or absence of an object. There are four basic types of limit switches, such as Whisker, Roller, Lever, and Plunger. Based on the application process, a limit switch may be developed using a blended combination of two types of limit switches.
Applications Of A Limit Switch
They are used in a variety of things in your daily lives. For example, whenever you open your refrigerator door, you may have noticed that a light goes on. That happens because the limit switch sensed that the door of the refrigerator is opened or closed. Therefore, it directs the light on or off as per the door function.
Another common application of limit switch you may have noticed in your house is while operating the garage doors – you will probably find a limit switch that stops the door’s movement when it has opened fully.
How Do They Work?
As has been discussed before, limit switches are a kind of electromechanical device that involves an actuator, which is connected to an electric switch mechanically. When the object comes in contact with components such as an actuator, the switch makes the electrical connection’s status to ‘make or break’. They are obtainable in various configurations, such as:
Normally open
Normally closed
Either of the two
Different Types Of Limit Switch Circuits
Microswitch
A microswitch is made from two limit switches working jointly and splitting/sharing a terminal. Here, it is critical to note that one limit switch would probably be normally open, and the other one would be normally closed. In other words, the switch configuration can be defined as Single Pole Double Throw or SPDT. The dashed line in the circuit is helpful to get an indication that both switches are mostly connected to one another mechanically and operate simultaneously.
When you connect a simple microswitch circuit to a designated lamp circuit, you will be able to see it working clearly. For example – if the circuit is inactive, you will see the red lamp to be ‘on’ as the machine is not being operated at the moment (No objects are triggering). However, as soon as the trigger gets pushed, the circuit activates with the green light turning on.
As far as its applications are concerned, you may have seen it in the assembly line or any additional moving mechanical parts. Limit switches can also be utilised to determine or count the number of passing items or identify the hydraulic cylinder’s position.
Proximity Sensor Vs. Limit Switch
Over the years, limit switches have started disappearing from the industrial applications and substituted by proximity sensors.
The difference between a proximity sensor and a limit switch is that the former has no mechanical moving parts. They perform the switching action with the help of electronic switches.
Even though proximity sensors are gaining immense traction these days, they don’t threaten the limit switch market because they outshine their counterparts in reliability as well as efficiency in operating in difficult settings. Limit switches are far more capable of handling optimum current values as compared to proximity sensors that make them more desirable in an industrial environment.
Limit Switch Uses
In most cases, a limit switch operates when a moving object or a component makes contact with an actuator, or an operating lever activates the switch. The limit switch then controls the circuit that regulates the machines and their movable parts. They can be installed for standard operations or as emergency devices to prevent malfunction in pieces of machinery.
Limit switches are a helpful addition to an industrial process. However, you must seek professional guidance to choose the right one for your needs.
