What Is a Positioner?
A Positioner is a device that performs positioning based on external commands.
It is used in combination with an actuator such as a motor or hydraulic cylinder, and is designed to move to a target position. They are used in machining and control valves, where high positioning accuracy, speed, and durability are required.
Applications of Positioners
Positioners are a type of positioning control device used in a wide range of equipment. The following are examples of Positioner applications.
1.Control Valves
Positioners are often used to control the opening degree of control valves. Positioners are sometimes referred to as control devices for control valves. Many products are sold with a positioner attached to the control valve.
They are often used in process plants. Typical examples are chemical plants, petrochemical plants, steel mills, and thermal power plants. Used to control the flow rate of reactive air and exhaust gas pressure.
2. Positioning in Automation and Assembly Lines
In automation and assembly lines, positioning of product parts is very important. The use of Positioners can achieve high positioning accuracy, leading to improved product quality and productivity.
Positioners are also sometimes used in industrial robots, which require advanced positioning. These are often used in assembly-line factories, and the automotive industry is one example.
3. Machining
Positioners are also used in the machining industry. High-precision positioning is sometimes required in machining.
The use of Positioners provides advanced positioning control, leading to improved product accuracy and shorter machining times. They are used in lathing, bending, welding, and other processes.
Principle of Positioner
Positioners generally acquire position information by means of a position sensing element. Based on this information, actuators such as motors and hydraulic cylinders are driven to move the workpiece to the target position with control accuracy, thereby performing positioning.
Specifically, optical and magnetic sensors are used as position detection elements. By measuring the difference between the target position and the current position with these sensors, position information can be acquired.
After acquiring position information, actuators are driven for positioning based on this information. Electric stepping motors, servo motors, and hydraulic cylinders are used as actuators. These actuators perform positioning based on control signals and move to the target position with control accuracy.
By combining position detection sensors and actuators with feedback control, more advanced positioning control can be achieved. Feedback control is implemented by adjusting the drive amount of the actuator based on the current position information obtained from the position detection sensor.
Types of Positioners
There are several types of Positioners. The following is an example of one type of Positioner.
1.Electro-Pneumatic Positioner
Electropneumatic Positioners are positioners that use an electrical signal input and air pressure for the positioning drive unit. Magnetic or optical sensors are used, and piezoelectric elements are used to control the positioner.
Positioners are often used for control valves. Many valves are sold that control the degree of opening by inputting air pressure and electrical signals.
2. Electro-Electric Positioner
Electroelectric Positioners are positioners that input electrical signals and use electricity for the positioning drive unit. Optical or magnetic sensors are used, and stepping motors or servo motors are used as actuators. Induction motors, which are commonly used for large valves, are also used.
3. Pneumatic Positioner
Pneumatic Positioners are positioners that input pneumatic signals and use air pressure for the positioning drive unit. They are used in places where explosion protection is required, such as in hazardous material facilities, and are suitable when electricity is not required.