ESM10A GE Application DCS System Board

Description

In industrial process computer control systems, distributed control systems (DCS) have become a mainstream control system. With the deepening of DCS application, the configuration work of DCS has also shifted from manufacturers to users. This is commonly referred to as user configuration. At present, the research on DCS user configuration work by industry insiders is limited to the study of DCS operation screen configuration. This article introduces the successful application of DCS in the production of hydrogen peroxide in our factory and my personal experience in practice, and puts forward some opinions on DCS user configuration.

2 System process flow
This production device includes two production lines: new and old. They all include five processes: hydrogenation, oxidation, extraction and purification, post-treatment, working solution preparation and recovery.

The hydrogenation process converts anthraquinone into anthraquinone or tetrahydroanthraquinone. The oxidation process directly oxidizes anthraquinone and tetrahydroanthraquinone with oxygen in the air, and converts them into anthraquinone and tetrahydroanthraquinone, while generating hydrogen peroxide. The function of extraction is to extract and recover hydrogen peroxide from the oxidation solution using non ionic water, producing a certain concentration of hydrogen peroxide solution. After purification treatment, the solution not only reduces the content of organic carbon, but also produces 27.5-35% of the product for sale in the market. The raffinate from the extraction undergoes post-treatment and regeneration before entering the next cycle of use. The production process is as follows:
2.1 Process requirements for control systems
2.1.1 Implement centralized monitoring of various unit operations, including monitoring and control of physical quantities such as temperature, pressure, flow rate, liquid level, etc. Dynamic parameter detection and control must be accurate and reliable.
2.1.2 Necessary remote control measures. For unexpected events such as power outages, the system should take corresponding protective measures to ensure remote control of key control points (valves, motors, etc.) in emergency situations or when needed.
2.1.3 Configure necessary alarms and interlocks.
2.1.4 Record important parameters and easily access real-time and historical trends.
2.1.5 It is possible to monitor the relevant parameters of relevant units or the operation of important equipment at any time.
2.1.6 The control system is easy to operate, with convenient parameter setting and adjustment, easy to operate, and a user-friendly operation interface.
2.1.7 The operator station displays the entire production process, modifies and prints various related parameters.
2.2 System Control Detection Points
There are many analog detection points for temperature and liquid level in this system, including 39 thermal resistors, 98 4-20mA analog inputs, 48 4-20mA analog outputs, 48 control circuits, and 26 switch inputs.

3 Hardware Configuration
When configuring the system hardware, it is necessary to comprehensively consider the overall situation, including meeting the control requirements of the production process, the characteristics of components such as on-site transmitters and actuators, transmission signal cables and DCS input/output cards, etc., and comprehensively analyze the rationality of the process, the economy of investment, the reliability of operation, and the convenience of maintenance. I have made the following configuration, and the system structure diagram is shown in Figure 1.
3.1 Redundant system server/operation station, equipped with 1 engineer station and 1 operation station, and reserved PC interface to meet the operational needs of the system. The operation station software is installed on the engineer station, which can be used as one operation station during system operation. Two operation stations participate in the operation at the same time during system startup. When the system is normal, use two operation stations for the operation management of the new and old systems.
3.2 Redundant high-performance hybrid controller, with hot backup between two controllers while receiving network data. If one of the controllers fails, the backup controller will automatically enter the working state. Complete functions such as regulation control, data processing, logical interlocking, and equipment control.
3.3 Redundant Ethernet and control network, the system is configured with 2 networks, and the monitoring layer is required to be open. The data communication system connects decentralized processing units, input/output processing systems, engineer stations, and operation stations to ensure reliable and efficient system communication. Therefore, a redundant state network configuration is adopted, and the communication protocol is TCP/IP standard protocol. The control network requires security.
3.4 In terms of I/O card configuration, more than 15% expansion space is reserved, and the types of cards are minimized. The entire system only has 5 I/O modules, thereby reducing the variety and cost of spare parts. When selecting temperature measurement modules, it is considered that the system has many temperature measurement points and the types of temperature measurement components are the same, all of which are platinum resistors. Therefore, using an RTD input module saves the investment cost of the transmitter.
3.5 Redundancy of all power supply devices and components.

4 System Functions
4.1 Engineer Station Functions
4.1.1 Used for program development, system diagnosis, control system configuration, database and screen editing and modification.
4.1.2 Generate any display screen and trend chart, and load them to the operator station through the communication bus. It can call up any defined system display screen in the system for modification and other work.
4.1.3 Through the communication bus, the system configuration information and related data of any decentralized processing unit in the system can be called up. Configuration data can be downloaded from the engineer station to the operation stations of various decentralized units. In addition, once the reconfigured data is confirmed, the system can automatically refresh its memory.
4.1.4 has offline and online full code download functions, which do not affect the safe and normal operation of dedicated devices. It can add or remove network devices online without affecting the normal operation of other network devices.
4.1.5 has the function of monitoring the operating status of the DCS system. This includes monitoring the operational status of each control station, operation station, and network communication status at all levels.
4.1.6 It has online configuration function. For example, changing the upper and lower limits of the range, adjusting control parameters, etc.
4.1.7 It has online display of all input/output and intermediate values on the configuration diagram.
4.1.8 Set operation protection passwords for the engineer station to prevent unauthorized changes to control strategies, applications, and system databases.
4.2 Operator Station Functions

The operation station is an interface for human-machine dialogue, where almost all control commands and status parameters are exchanged. On the operation station, various process parameters on site can be displayed on various flow charts, such as controlling drive devices, switching control methods, adjusting process settings, etc. Each analog and digital quantity in the system can be monitored, and alarms can be displayed and confirmed, operation guidance can be recorded, operation logs can be recorded, operation information such as changing set values, manual/automatic switching, and time can be recorded. Historical trend charts can be displayed, and reports can be printed regularly. Simple operation, meeting the requirements of operational control and production management.