Design of Remote Automation Instrument Power Supply
In the industrial process automation and system integration, there are a large number of distributed instruments and actuators, which need to be powered by AC or DC power supply. The AC power supply is mainly used in large mechanical instruments and control systems, and most of the actuators are powered by DC power supply. With the development of modern process automation technology and the requirements of system reliability, the design of DC power supply has become a major work in the design of distributed Instrumentation application system. In order to ensure the safety and reliability of the system, the power supply design should focus on the following aspects:
First of all, the selection of power should be careful, taking into account the requirements of the instrument. In the selection of the power supply of the instrument, the nameplate working voltage of the instrument and its power must be noted. It can be used to select the power supply of the instrument with the rated power, over-voltage and over-current protection, and the power supply of the instrument should be reliable, long-term stable and continuous voltage output.
Second, the protection of overvoltage and overcurrent is to be considered, because the stability of the instrument output is essential for the normal operation of the system. Overvoltage and overcurrent protection should be built in the design of power supply to ensure the safe and reliable operation of the system. In general, the external overvoltage protection device needs to be provided.
Third, the design of power supply should try to suppress interference, and the design of power system can adopt the method of power conversion to reduce the harm of electromagnetic interference and dynamic load interference to the system.
Fourth, the design of power system should provide output isolation. Since the output of power supply is used as the power supply of distributed instruments, in order to ensure the safety of distributed instruments, the output of power supply must be well isolated from the grid and noise.
Fifth, the power supply is designed to be modular, so as to realize the freely combination of power and provide power support for flexible application.
The above design points are usually taken into account when designing the power supply of distributed instruments. With the development of process automation technology and distributed instruments, the automation power supply design has been further expanded and developed, such as the design of efficient power supply, the design of digital power supply and the design of embedded power supply, which complete the automation power supply from many aspects.
