Determine the control mode of the electric actuator according to the production process control requirements
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Author: - Source: - Post Time: 2013-3-7 10:23:33
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Determine the control mode of the electric actuator according to the production process control requirements
Electric actuator control mode
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Switch type
(open loop control)
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Switching electric actuators generally control the opening or closing of the valve. The valve is either in the fully open position or in the fully closed position. Such valves do not require precise control of the medium flow. It is particularly worth mentioning that switch-type electric actuators can be divided into split structures and integrated structures due to different structural forms. This must be explained when selecting the type, otherwise it will often occur in the field installation and the control system conflicts, etc.
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1. Split structure (commonly referred to as common type): The control unit is separated from the electric actuator. The electric actuator cannot realize the control of the valve separately. It is necessary to add the control unit to realize the control. Generally, the external controller or control cabinet is used. Matching. The disadvantage of this structure is that it is not easy to install the whole system, increase wiring and installation costs, and is prone to failure. When the fault occurs, it is not easy to diagnose and repair, and the cost performance is not satisfactory.
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Second, the integrated structure (commonly referred to as the integral type): The control unit is integrated with the electric actuator, which can be operated locally without external control unit. The remote control can be operated only by outputting relevant control information. The advantage of this structure is that it facilitates the overall installation of the system, reduces wiring and installation costs, and is easy to diagnose and troubleshoot. However, the traditional integrated structure products also have many imperfections, so the intelligent electric actuators are produced.
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Adjustable type (closed loop control)
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The adjustable electric actuator not only has the function of a switch-type integrated structure, but also precisely controls the valve and regulates the medium flow.
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First, the control signal type (current, voltage). The control type electric actuator control signal generally has current signal (4~20mA, 0~10mA) or voltage signal (0~5V, 1~5V). The type and parameter of the control signal must be specified when selecting the type.
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Second, the work form (electric open type, electric off type). The working mode of the regulating electric actuator is generally electric opening type (taking 4~20mA control as an example, the electric opening type means that the 4mA signal corresponds to the valve closing, the 20mA corresponds to the valve opening), and the other is the electric switching type. (For example, 4~20mA control, the electric open type means that the 4mA signal corresponds to the valve opening, and the 20mA corresponds to the valve closing)
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