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Electrical valve positioners are widely used in everyday life, with a wide variety of products available. Depending on the different situations, they can be divided into the following types of locators. The editor will introduce it to you now. 1: Depending on whether the input signal to the valve positioner is digital or analog, they can be divided into fieldbus electrical valve positioners and conventional valve positioners. 1: The input signal for the fieldbus electrical valve positioner is a digital signal from the fieldbus. 2: The input signal for a standard valve positioner is an analog pressure signal, or a current or voltage signal. II: Based on whether the valve positioner is equipped with a CPU, they can be divided into intelligent electrical valve positioners and ordinary electrical valve positioners. 1: Intelligent electrical valve positioners come equipped with a CPU that can handle various intelligent calculations; for example, they can perform nonlinear compensation for the forward channel. Fieldbus electrical valve positioners may also include functional modules such as PID to carry out corresponding calculations. 2: Ordinary electrical valve positioners do not have a CPU; therefore, they lack intelligence and are unable to perform any intelligent calculations. III: Based on the direction of movement, they can be divided into single-direction valve positioners and double-direction valve positioners. 1: The two-way valve positioner acts on both sides of the cylinder in the piston-type actuator, functioning in two directions. 2: When a one-way valve positioner is used with a piston actuator, the valve positioner functions in only one direction. IV: Based on the sign of the gain of the input and output signals of the valve positioner, they are divided into feedback valve positioners and forward-acting valve positioners. 1: As the input signal to the reaction valve positioner increases, the output signal decreases; therefore, the gain is negative. 2: When the input signal to a direct-acting valve positioner increases, the output signal also increases; therefore, the gain is positive. Above, we have introduced the 4 main classification criteria for electrical valve positioners. If you are not sure which one to choose in daily life, feel free to read more articles like this one; we hope it will be helpful to you.