How to Choose a Limit Switch?

A limit switch is a device that uses the collision of mechanical moving parts to cause contacts to connect or disconnect the control circuit, thereby achieving a certain control purpose. It cooperates with other equipment to form more complex automation equipment in the industry. Therefore, choosing a more appropriate limit switch will make the entire automatic control system more reasonable and efficient.

Setting the limit switches depends on the type and location of the limit switches you are using.

The first thing you need to do is determine where the limit switch is and what it will be used to detect. This will give you an idea of what size and type of switch you need.

Once you have the correct limit switch, you need to secure it in place. Standard limit switches have pre-drilled holes that allow fasteners to hold the switch in place. If you are installing a limit switch for the first time, you may need to drill some holes. To check the position of a switch, you should first hold the switch in place to ensure it actuates correctly.

The next step is to connect the limit switch to the circuit. Contacts can be normally open, normally closed, or a combination of both. Finally, you should always test that the limit switch activates in the correct position and adjust if necessary.

We use limit switches for many different reasons. Let’s look at some of the most common reasons/applications we use them.

- Detect the presence of liquid level

- Count objects and items

- Detect range of motion

- Detect positioning within the system

- Maintain travel restrictions

- They can break the circuit when an unsafe situation occurs

- Detect the speed of objects

There are several key points in selecting a limit switch.

1. Select the limit switch according to the application scenario and control object.

Universal limit switches are usually used when the machine is not moving very fast. Roller ram limit switches should be used when the machine is operating on a path that is not suitable for installing a roller ram limit switch.

Furthermore, when very high efficiency, reliability, and accuracy are required, another type of switch should be chosen, namely a proximity sensor.

2. Select the structural form of the limit switch according to the movement characteristics of the machine.

Shell: According to the load of the limit switch, it is divided into light load and medium load. The shell material is mostly plastic. For heavy loads and super heavy loads, the outer casing material is mostly metal. Therefore, suitable housing needs to be selected.

Actuator: Choose different actuators according to the shape and movement direction of the detection target. Types of actuators include roller plungers, top plungers, roller levers, adjustable roller levers, adjustable levers, fork levers, and coil springs.

3. Select the limit switch according to the rated voltage and rated current of the control circuit.

4. Select the appropriate limit switch based on environmental factors such as ambient temperature, resistance to vibration and shock, and protection level. For example, waterproof limit switches can be used in industrial applications that require water, oil, and dust resistance.

The above briefly introduces the issues that need to be considered when selecting and setting limit switches. If you want to know more or order limit switches for your company, please contact us.

UG Controls is a custom valve actuators and accessories manufacturer. Its main business is the import and export of various automation equipment and technologies. UG Controls is a proprietary business solution for chemical engineering, water, oil and gas, power plants, manufacturing, food and beverage and more. We also have very distinguished engineers who have extensive and in-depth knowledge in their respective fields to provide ideal solutions to get the most out of our products.