How to classify pneumatic actuator accessories and valve positioners?
For valves, the positioner in the accessories of the pneumatic actuator can help to better produce valves and facilitate the production of enterprises. How are valve positioners classified?
1. According to the classification of input signals, the valve positioner has two kinds of input signals: analog signal or digital signal, which can be divided into ordinary valve positioner and field bus electric valve positioner. The input signal of the common valve positioner is the analog air pressure or current, voltage signal, and the input signal of the field bus electrical valve positioner.
2. According to the gain symbols of the output and input signals of the valve positioner, it is divided into positive action valve positioner and reaction valve positioner. When the input signal of the positive acting valve positioner increases, the output signal also increases, so the gain is positive. When the input signal of the anti reaction valve positioner increases, the output signal decreases, so the gain is negative.
3. It can be divided into one-way valve positioner and two-way valve positioner. When the piston actuator uses a one-way valve positioner, the valve positioner only works in one direction, and the two-way valve positioner works on both sides of the piston actuator cylinder.
4. It can also be classified according to the detection method of feedback signal.
