This paper introduces a new type of instrument dcs system, which is built on the embedded platform with its own intellectual property software and hardware technology. Compared with the traditional industrial computer solution, the system has flexible application and reliable operation. The performance is stable, the cost is low, etc. The article concludes with a successful case of the system. This case enriches the customer company's product line and provides the company's customers with a new type of instrument with low cost, flexible configuration and convenient on-site debugging. DCS system.
I. Application Status of Automation Instruments Automated instrumentation technology is already a relatively mature technology in China, and its products are also diverse and the categories are relatively complete. Various self-instrument products such as temperature control table, PID meter, flow totalizer, electrical instrument, etc. are widely used in various industries such as chemical industry, kiln, test box and water treatment.
Instrument manufacturers consider the necessity of centralized instrument products to the central control system. Generally, the instrument will be equipped with a 485 communication interface. In this way, as long as the customer needs it, the automation instrument located on the site can be connected to the central control computer via the 485 bus. In this way, the central control computer can use the configuration software to string all the instruments on the 485 bus and configure them in real time. This mode is shown below: 
This instrumentation DCS system based on a central control computer has the following characteristics:
1. Flexible networking;
2. It can be compatible with secondary instruments of different manufacturers and different categories;
3. A specific configuration project needs to be made for each system;
4. Due to the reason of 3, on-site debugging is required, and the debugging steps are cumbersome;
5. The reliability of his depends on the superposition of the reliability of the industrial computer, configuration software and operating system;
6. The cost component of the program: the purchase cost of the central control computer + the configuration software license fee + the operating system license fee + the configuration project development cost + the on-site commissioning fee.
Second, the composition of the embedded instrument DCS system For the DCS system based on the central control computer instrument, his shortcomings are high program cost and cumbersome on-site debugging.
The instrument DCS system introduced in this paper is a brand-new technical architecture. This instrument DCS system not only has all the advantages of the former, but also compensates for its shortcomings. The system basically does not need to make configuration engineering when in use. It can be used in the field according to the regulations, which greatly saves the time of production configuration and on-site debugging. In addition, compared with the previous scheme, the cost is much lower.
2, 1 hardware composition ï¬ ARM series 32-bit high-performance embedded CPU
ï¬ Memory 32M, FLASH 32M
ï¬ Integrated Ethernet, serial port, CF card slot, print port and other peripheral interfaces ï¬ TFT true color LCD display ï¬ Four-wire resistive high-performance touch screen 
The instrument DCS system based on the embedded CPU is characterized by:
1. High reliability, the embedded system has greatly improved the reliability by eliminating many unnecessary peripherals and interfaces of the industrial computer;
2, low energy consumption, this system has energy consumption of about 8W, with very low energy consumption;
3. The cost is low. Compared with the industrial computer, the embedded system has the cost advantage that other systems cannot match.
2, 2 software system composition ï¬ Adopt industrial-grade multi-tasking embedded operating system with independent intellectual property rights ï¬ Integrated TCP/IP protocol stack, serial port printing port driver, file system ï¬ Embedded configuration technology with independent intellectual property rights ï¬ Independent intellectual property rights Configuration development environment ï¬ Agreement for integrating major domestic and international instrument manufacturers' instruments 
As can be seen from the above figure, this software system is quite lightweight. Compared with the OS of the industrial computer, the system has the following characteristics:
1. The OS structure is simple, the level is small and clear and distinct;
2. The operating efficiency of the OS is high;
3. There is no need for the customer to pay an additional license fee for the OS.
Third, the embedded instrument DCS system configuration operation system embedded instrument DCS system configuration operation system uses a typical multi-tasking system mode, so that DCS and instrument serial port communication, with higher communication efficiency.
The configuration of the system is built-in and does not require additional customer charges, saving customers money.
The technical framework for configuring the runtime environment is shown below: 
The main technical features of the configuration operating environment:
ï¬ Built-in standard configuration project dedicated to automation instruments ï¬ The set value and measured value of the instrument can be recorded in the CF card. ï¬ Intelligent identification of the instrument model on the 485 bus. ï¬ Call the corresponding instrument parameter setting interface to perform parameters according to the recognition result. Settings ï¬ Query data can be queried according to the set conditions. ï¬ Built-in alarm mechanism to complete the recording of alarm data. The configuration runtime environment includes the following modules: 
Data recording module: The data recording module is used to record the real-time measured values ​​of each meter on the 485 bus, and save the data in the CF card;
Instrument parameter setting module: dynamically identify the instrument model of each station number on the 485 bus, and call the corresponding instrument parameter setting interface according to the recognition result, the user can set the parameters of the instrument.
Historical curve module: displayed in the form of a graph based on the data recorded in the CF card.
Real-time curve module: dynamically displays the measured values ​​and set values ​​of each meter on the 485 bus in a curved form.
Report generation module: According to the data recorded in the CF card and the query range set by the user, the generated record report is displayed.
Print module: The corresponding report or curve can be printed according to the user's needs.
Flowchart module: graphically displays the working status of each link of the instrument DCS system and its position in the system.
Data upload module: The recorded data can be uploaded to the PC in CSV format, and the PC can import the data into the database or perform comprehensive processing through EXCEL.
In addition, in order to quickly customize the embedded instrument DCS system based on their products for the instrument manufacturers, the company also provides the secondary development environment LEVIStudio of the instrument DCS configuration. With LEVIStudio, you can quickly customize the suitable instrument manufacturers for their products. Instrument DCS system.
Based on the above various factors, the scheme of embedded instrument DCS system and industrial computer is compared as follows: 
Fourth, application case: Instrumentation DCS system based on Y company instrument products
Y company is one of the famous instrument manufacturers in China. Its instruments and related products are sold at home and abroad. The instruments produced by the company are well received by customers because of its stable performance and fast service.
LEVIStudio is the main tool for the Y company to customize the instrument DCS system. Due to its "what you see is what you get" development characteristics, the related customization work was quickly completed.
The main functions of Y company's instrument DCS system are as follows: 
Figure [6] Real-time data screen
Whether the intelligent detection instrument is online, “no definition†means that the meter does not display the PV value of the instrument online. Clicking on the instrument screen of each channel will display in red if there is an alarm. 
Figure [7] Real-time curve screen
The model of the intelligent identification meter displays the real-time graph of the PV, SV, MV and other key data of the meter. 
Figure [8] Data bar graph bar graph showing PV value if the alarm will be displayed in red 
Figure [9] Real-time multiple curves
Display the PV curve of each channel in one picture;
You can dynamically change the scale of the curve to hide or display a curve 
Figure [10] The field control flow chart shows the operation status of each meter in a flow chart to simplify the process flow and make it easier to understand. 
Figure [11] Setting of instrument parameters
The instrument that automatically recognizes the hmi hook changes the instrument parameter setting screen corresponding to the identified meter to synchronize any operating parameters of the meter. 
Figure [12] The data report screen queries the data of the CF card in the HMI in the form of a report. Supports the scroll bar to drag and display the data. The query time can be changed to upload the query result to the host computer. 
Figure [13] Overall interface layout
Windows-style start menu One-click function Navigation flapping function Password protection to ensure data modification permissions and security V. Overview Because the embedded instrument DCS system is fully functional, reliable, and stable, it brings a rich Economic and social benefits:
1. Enriching Y's product line, making Y company's instrument product users have a more cheap and more reliable solution;
2. Greatly reduce the on-site debugging time of the product and improve the efficiency of the company's sales staff and after-sales support personnel;
3. Due to the DCS system of the instrument, the customer saves more cost and time, and does not need to maintain the industrial computer at the site.
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