Abstract : This paper introduces the structure, functional characteristics, and application of special function modules of the newly launched modular bus-type intelligent controller from Lanli Oriental Company. Keywords : Variable frequency water supply, intelligent control, modular 1 Introduction Currently, there are various control schemes for variable frequency constant pressure water supply. One is an intelligent constant pressure water supply controller with a single-chip microcomputer as the control hub; another is an intelligent control system with a PLC as the control unit; and a third is to use the water supply control board built into the frequency converter and the software functions of the frequency converter itself to realize the control function. Among them, the intelligent dedicated controller with a single-chip microcomputer as the core has the advantages of not requiring user programming, simple debugging, and a good display interface compared with other schemes, and has been welcomed by users. Beijing Lanli Oriental Company has been committed to the research and development and production of intelligent constant pressure water supply controllers, and with many years of experience and application practice in the water supply industry, it has taken the lead in developing a modular bus-type intelligent controller for water supply in the industry. To enable users to better understand this product, the structure, performance characteristics, and application of special modules of the CPS-21E series water supply controller are briefly introduced. 2. Structure of the CPS-21E Series Controller This controller features an advanced modular structure and a fully modular design, aligning with the current trend in advanced industrial control systems. For example, Siemens S7-300 and OMRON CQM1H both employ modular designs. Its main advantage lies in the user's ability to freely combine and match modules to meet the needs of systems and applications of varying sizes. Modules can be installed side-by-side compactly or separately depending on the distribution of system equipment. When installed separately, the maximum distance between modules can reach 1000m. The main unit module has an RS-485 interface for communication with the host computer, and a nine-pin port on the right side serves as the interface for connecting the display unit. Both the main unit module and expansion modules have a station number setting dial and a pump status selection DIP switch, as well as a digital window displaying the pump number and input/output I/O indicator lights. These digital and indicator lights provide users with a clear view of the pump number and input/output status. [b][align=center]For more details, please click: Modular Bus-Type Intelligent Water Supply Controller[/align][/b]