Abstract: This article mainly introduces the system integration of Delta Automation products in a distilled water machine, demonstrating the high cost-effectiveness and technical advantages of Delta Automation products in the integrated application of electrical control systems, illustrating that Delta Automation products are the best choice for the equipment manufacturing industry. Keywords: PLC, HMI, macro instruction, RS485 communication 1 Introduction Distilled water, simply put, is the product of water vapor condensation. Chemically, it is called pure water. Pure water with the chemical formula H2O should not contain any other impurities and is an important raw material in industrial production. Distilled water has a wide range of applications, mainly used in the formulation of raw materials for chemical products and the processing and manufacturing of food, pharmaceuticals, cosmetics, etc., such as beverages and medical infusion saline. The distilled water machine introduced in this article is a dedicated distilled water production equipment. The electrical control system of this distilled water machine is fully integrated with Delta Automation products to achieve process control and technical requirements for customers. 2 Distilled Water Machine Control System and Process 2.1 Control Process The distilled water machine control system mainly realizes the control of physical quantities such as temperature, pressure, and conductivity inside the controlled raw material tank to meet the requirements of different product specifications. The control system can set relevant parameters according to different product needs, set upper and lower limits for parameters, and display the changes in relevant parameter values ​​in real time, control the opening of each pipeline valve, thereby ensuring that the product is produced according to the preset process parameters. When the limit is exceeded, there will be an alarm display and related protection actions. At the same time, according to customer needs, after the product is processed, parameter reports are printed and stored (electronic file format *.JPG stored in a universal USB disk). The accessories listed in the table above are the main components of the production line control system. In addition, low-voltage electrical appliances (low-voltage circuit breakers, relays, master buttons, indicator lights, etc.), detection sensors (K-type thermocouples, PT100 thermal resistors, conductivity sensors, pressure sensors, liquid level sensors, analog signal transmitters, etc.), micro printers and other electrical components are also included, which will not be elaborated here. 2.2 System Principle (1) System Principle Design: The system principle design is shown in Figure 1. The system is constructed by Delta PLC as the main controller, and is connected to Delta touch screen human-machine interface through RS-485 bus to form a management operation and printing record system. The system hardware configuration is shown in Table 1. Utilizing the rich communication port functions of Delta's HMI, three COM ports can be provided to users for convenient communication and connection with peripheral industrial control equipment. Figure 1 Control System Architecture (2) System Communication Principle Design: COM1: RS232 communication mode connects to the lower PLC to set and read various process parameters of distilled water equipment and products. COM2: RS485 communication mode connects to the micro printer. Utilizing Delta's HMI macro instruction programming function, it processes the free port communication protocol and sends the Chinese characters, English letters, and numbers to be printed to the printer. It can print product process parameter reports as textual basis for product quality inspection and archive data. 3 Software Development 3.1 PLC User Program The PLC user control program mainly realizes analog data acquisition and calculation conversion, and over-limit alarm output control. It is necessary to calculate the digital display value according to the analog signal range of the sensor and transmitter, and write the alarm processing program according to the process requirements provided by the user. Figure 2 is an excerpt of the PLC control program, for reference only. Figure 2 Process Parameter Alarm Ladder Diagram 3.2 HMI User Program The main interface of the system control is shown in Figure 3. Figure 3 shows the main interface of the system control. Operators must log in to the control system using a password. Operators 1 through 3 have different response levels, decreasing in that order: Operator 1 > Operator 2 > Operator 3. That is, using the password for Operator 1 allows login for Operators 2 and 3. The three buttons are interlocked; pressing one button disables the other two, achieved through macro instructions. The operator screen's CYCLE macro is shown below: Operator 1 button's active bit is $10003.0, in the OFF state. Pressing the "Operator 1" button executes the macro instruction as follows: Operator 2 button's active bit is $10004.0, in the OFF state. Pressing the "Operator 2" button executes the macro instruction as follows: Operator 3 button's active bit is $10005.0, in the OFF state. Pressing the "Operator 3" button executes the macro instruction as follows: Utilizing the macro instruction function provided by the human-machine interface can achieve twice the result with half the effort. The above program is an application example, implementing a multi-user login control system with different permission levels, providing product design and development technicians with powerful and flexible programming capabilities. The distillation water machine parameter data screen is shown in Figure 4. Figure 4 shows the parameter data display system, which can display real-time changes in various process parameters such as inlet water temperature, outlet water temperature, pressure, liquid level, and conductivity, facilitating operator control of the equipment. In case of an over-limit alarm, the system will display a scrolling alarm message in a carousel format, making it easy for the operator to issue protection commands. The new version of Delta's HMI software provides a "Save Screen" function button, which can save a specific HMI screen as a JPG file to a USB drive, conveniently storing and printing industrial process parameter reports. After pressing the parameter save button in Figure 4, the screen will be saved to the USB drive as a YY-MM-DD-screen number.JPG file, named with the date + screen number. If the USB drive is not plugged into the back of the HMI, a "storage drive not found" alarm will be displayed. Pressing the "Limit Setting" button in Figure 4 will jump to the temperature and pressure high and low limit setting screen, as shown in Figure 5. Different parameter values ​​can be entered using the numerical input buttons to meet the needs of different product specifications. Figure 5. Process Parameter Limit Setting. Pressing the "Parameter Calibration" button in Figure 4 will switch to the temperature and pressure parameter calibration screen. The parameter values ​​to be calibrated can be entered using the value input button. This eliminates fixed deviations between the sensor detection results and standard measuring instruments, ensuring consistency between the system display and measurement and the standard instrument, similar to the sensor signal zeroing process. Pressing the "Print" button in Figure 4 will print a data report using the micro printer, as shown in Figure 6. Report printing is also achieved through Delta's powerful macro instructions in the HMI. Figure 6. Report Printing. Other printing subroutines for pressure, level, conductivity, operator, date, and time are similar to the inlet and outlet water temperature printing subroutines mentioned above and will not be described in detail. The CLOCK macro instruction loops through the main program, calling the printing subroutines in a time-sharing manner to print parameter data. 4 Conclusion Providing cost-effective and perfectly integrated solutions is Delta Electronics' marketing strategy, and providing stable and reliable system integration solutions is a guarantee for serving customers. The distilled water machine equipment control system developed in this project integrates Delta's HMI, PLC and other automation products, realizing a stable and reliable system for customers. Since its commissioning, the equipment has been operating normally, not only meeting the on-site process requirements, but also improving the controllability of product quality and equipment efficiency, once again proving that Delta Electronics is a trustworthy partner for customers. References [1] Delta DVP-PLC Application Technology Manual Program Section [2] Delta DOP Series HMI Application Technology Manual