In the electrical control system, the function of the limit switch is to realize the detection of sequence control, positioning control and position state. It is used to control the stroke and limit protection of mechanical equipment. Structure: It consists of an operating head, a contact system and a housing.

In actual production, the limit switch is installed in a pre-arranged position. When the module installed on the moving part of the production machine hits the limit switch, the contact of the limit switch moves to realize the switching of the circuit. Therefore, a limit switch is an electrical appliance that switches a circuit according to the travel position of a moving part, and its working principle is similar to that of a button.

Limit switches are widely used in various types of machine tools and hoisting machinery to control their travel and perform terminal limit protection. In the control circuit of the elevator, the limit switch is also used to control the speed of opening and closing the car door, the limit of the automatic opening and closing of the door, and the upper and lower limit protection of the car.

Limit switches can be installed on relatively stationary objects (such as fixed frames, door frames, etc.) or moving objects (such as driving, doors, etc.). When the animal approaches the still object, the linkage of the switch actuates the contacts of the switch causing closed contacts to break or open contacts to close. The action of the circuit and mechanism is controlled by the change of the open and closed state of the switch contact.

Application of limit switch in industry

The real use of the limit switch is in industry, where it cooperates with other equipment to form more complex automation equipment.

There are many such limit switches on the machine tool, which are used to control the movement of the workpiece or the stroke of the automatic tool feed to avoid collision accidents. Sometimes the limit switch is used to automatically change the direction of the controlled object between the two specified positions, so as to obtain continuous reciprocating motion.

 For example, when the trolley for automatic material transportation reaches the end point and touches the limit switch, the dumping mechanism is turned on, and the materials in the car are turned over and returned to the starting point. After reaching the starting point, touch the limit switch of the starting point again, connect the circuit of the charging mechanism, and start to automatically load the car. If it continues like this, it will become an automatic production line, which can work around the clock without human management, saving people's physical labor.

Eaton Mueller's limit switch models are available in a variety of configurations. AT 0, ATR and AT 4 limit switches have a modular system, degrees of protection NEMA 4, 23 and IEC IP 65, fully insulated, protected against personnel, positive operating, suitable for use with electrical equipment according to IEC/EN 61 131-2 .Safety function with positive opening contacts according to IEC/EN 60 947-5-1, equipment for global market: and UL/CSA/IEC/CE.

The LS Titan position switches from the Eaton Moeller range are used for safe, accurate and reliable position detection. They allow smooth and safe operation and can be optimally adapted to any application. Position switches also help to improve process and personal safety standards. Available with one NC and one NO contact, or two NC contacts. Additionally, all operating heads in the LS Titan range can be rotated 4 x 90 degrees for quick and secure installation. Below are some LS series models.