Main reference:
[1] Chang Jie, Wang Yi, Li Jie, Chen Zhengwen. A summary of the existing architecture of industrial communication networks and the development strategy of future operators [J]. Telecommunications Science, 2017, 33(11): 123-133.
[2] Li Jie, Zhang Dong, Chang Jie, Yang Zhen. The status quo and key technology analysis of industrial connection for intelligent manufacturing [J]. Telecommunications Science, 2017, 33(11): 146-153.
Table of contents
1. ISA-95 standard reference model
2. RAMI 4.0 Reference Architecture
3. Architecture of Industrial Internet Network
4. IT-OT Converged Architecture
5. Three types of application scenarios and eight requirements for industrial networks
The Industrial Internet, Industry 4.0, and Made in China 2025 all come down in one continuous line, and they are all oriented towards intelligent manufacturing and trying to achieve vertical integration, horizontal integration, and end-to-end integration of industrial manufacturing.
| definition | Purpose | |
| vertical integration | Focus on the integration process of product design, manufacturing process and product life cycle , and realize the integration from enterprise management, production execution, production monitoring to field equipment. | Based on the networked manufacturing system in the smart factory, it realizes distributed production and replaces traditional centralized central control production. |
| horizontal integration | The traditional supply chain, the linear value organization method from factory to sales network is networked to form a network manufacturing ecology . | The factory is intelligent, and the production unit is smaller, which is convenient for personalized production. Realize value ecological reconstruction and business model innovation. |
| end-to-end integration | Examine intelligent manufacturing from the perspective of process flow , including flexible integration of product life cycle processes including R&D, raw material procurement, logistics, warehousing, production, sales, delivery and service. It is mainly reflected in the parallel manufacturers, which will form the enterprise's integrated platform system through the integration platform of unit technology products, and develop towards the factory's comprehensive capability platform . |
Completing end-to-end integration in a single industry chain can achieve better product experience and maximize benefits, thereby enhancing the control of the industry chain. |
1. ISA-95 standard reference model
The ISA-95 standard reference model is shown in Figure 1, which is divided into five layers. MES is in the middle layer between the enterprise business planning layer and the underlying control layer, focusing on the manufacturing execution of the enterprise, and its main functional scope corresponds to the manufacturing execution layer; at the same time, MES also considers the system selected by the business planning layer and the process control layer information exchange between them.
| level | Function |
| layer 0 | actual production or manufacturing process |
| Tier 1 | Monitoring and handling of labor or sensors in the production process, as well as the corresponding actuators |
| layer 2 | Manual or automatic control action to keep the process stable or under control |
| layer 3 | The scope of concern of MES includes workflow activities to produce desired products, coordination and optimization of production processes, maintenance of production records, etc. |
| layer 4 | Various business-related activities required for the management of a manufacturing organization, including establishing basic shop floor scheduling, determining inventory levels, and ensuring that materials are produced in the right amount at the right time, etc. |
| Note: The interface between layer 3 and layer 4 is usually the interface between factory production planning and operation management and workshop coordination | |
2. RAMI 4.0 Reference Architecture
RAMI 4.0 elaborates the model from three levels:
- 1st dimension (left vertical axis). Starting from the architecture from the perspective of IT, borrowing the ISO/OSI seven-layer model, the lower layer provides interfaces for the upper layer, and the upper layer uses the services of the lower layer.
- 2nd dimension (left horizontal axis). Starting from the architecture from the perspective of business process (production process), the complete life cycle starts from planning, to design, simulation, manufacturing, sales and service.
- 3rd dimension (right horizontal axis). Starting from the framework of the application perspective, it mainly focuses on the manufacturing process control and management functions of products in the industrial production environment. In addition, Industry 4.0 not only pays attention to the factories, workshops and machines that produce products, but also pays attention to the products themselves and the cross-enterprise collaboration outside the factory. Therefore, the "product" layer is added at the bottom of the factory, and the "connected world" layer is added at the top of the factory.
3. Architecture of Industrial Internet Network
Including the internal network of the factory and the external network of the factory (as shown in the figure), the internal network of the factory presents a "two-layer and three-level" structure. The two-layer mainly refers to the two-layer technology heterogeneous network of the OT network and the IT network, and the third-level refers to the current factory management level. Including field level, workshop level, factory level/enterprise level 3 layers, the network configuration and management strategies between each layer are independent of each other.
| Factory internal network | Factory external network | ||
| Factory OT network | Factory IT Network | ||
| effect | Used to connect controllers (PLC/DCS/FCS, etc.), sensors, servers, monitoring equipment, etc. on the production site. | It is mainly composed of an IP network, and realizes interconnection and security isolation with the Internet and the factory OT network through a gateway | IT systems (ERP, CRM, etc.) are deeply coordinated and integrated with the Internet, hosting IT systems on Internet cloud platforms, or using enterprise IT software services provided by SaaS service providers. |
| level | On-site level: production equipment/instrument/IO, etc. Control level: SCADA/HMI/PLC, etc. |
Workshop level: MES Factory level: ERP/PLM/SCM/CRM, etc. |
Interconnect level |
| Network Features | Data reliability is guaranteed, and the demand for large network bandwidth increases. There are various collection interfaces and protocols, and it is necessary to adapt to various collection interface protocols. |
The exponential growth of the underlying data volume and the penetration of high-bandwidth applications such as video into the industry have placed higher and higher requirements on network bandwidth, delay and jitter performance | High requirements on reliability, bandwidth, delay performance, business form, etc. |
| network technology | Wired first, wireless second. Fieldbus, Industrial Ethernet, WiFi, Industrial WSN, 5G, etc. |
Wired bearer-based. Commercial Ethernet, WiFi, RFID, Bluetooth, ZigBee, 5G, etc. |
The Internet, public mobile networks, dedicated lines, etc. The existing solution for dedicated lines is to use unlicensed frequency bands to expand to public areas. |
| future trend | Unified Network for Latency-Sensitive Industrial Ethernet | Industrial PON, etc. drive the upgrading of wired networks, and a small number of large-scale factories have built their own dedicated cellular mobile networks | |
4. IT-OT Converged Architecture
The existing structure is mainly concentrated in the internal factory of the manufacturing enterprise , relying on the network, adopting the strategy of vertical layering and horizontal decentralization. The vertical layer mainly refers to the ISA-95 reference model, including four layers of field level, control machine, workshop level and factory level. Due to the characteristics of on-site operations in the factory, business processing locations are scattered, software and hardware conditions are uneven, and there are many types of equipment that need to be maintained . This requires the system to simplify system maintenance with simple, efficient, and intelligent technical means. The outside of the enterprise uses the Internet, dedicated lines, and mobile networks to connect with partners, users, and smart devices.
Therefore, the layered architecture of the industrial network is mainly divided into field level, control level, workshop level, factory level and interconnection level . The interconnection level is mainly located outside the factory and is mainly carried by the operator's public network. It is composed of the Internet, public mobile networks and Dedicated line and so on. Among them, the dedicated line lacks the "on-demand" capability, and the existing solution is that some enterprises use unlicensed frequency bands to extend the "connection capability" to public areas.
5. Three types of application scenarios and eight requirements for industrial networks
Existing industrial communication network application scenarios mainly include three categories: wide-area application scenarios, factory-level application scenarios, and field-level application scenarios, which are described in detail as follows.
| scene definition | way of communication | shortcoming | |
| Wide Area Application Scenarios | Wide-area network access and communication among multiple factories, collaborative design, supply chain collaboration, logistics among multiple factories, etc. | Generally, the Internet, dedicated line network or VPN virtual private network are used | |
| Factory-level application scenarios | Mobile office applications, mobile MES applications, safety management (wireless video surveillance and wireless inspection), energy-saving management, trunking calls, and intelligent material transportation and distribution in the factory area, etc. | Generally, the coverage method of Ethernet + Wi-Fi is adopted | Complex cable deployment, long construction period, high maintenance cost, large energy consumption and space occupation; Wi-Fi has problems such as incomplete network coverage, multi-Wi-Fi deployment, unstable network signals, and security |
| Field-level application scenarios | Data collection and analysis, operability and visualization of production process data, equipment fault information, and resource monitoring | General use of industrial control bus | The wiring cost is relatively high, some places are not easy to wire, the industrial control bus data collection is not comprehensive enough, the networking method is relatively simple, and new application scenarios require more diverse topologies |
The eight requirements of the industrial communication network are described in detail as follows.
| Type of requirement | performance requirements | ||
| 1 | Connection of field devices to plant control systems | Interconnection of underlying I/O, control units such as PLC, and upper computers such as IPC | It is necessary to greatly increase bandwidth and scale while ensuring reliability and delay performance, and ensure data intercommunication and physical intercommunication between different protocols |
| 2 | Connection requirements between field devices and private cloud platforms | Field devices are directly connected to IT systems such as MES running on the private cloud, across the host computer through Ethernet or optical network | 需要通过网络和各类现场工业通信协议的高效互通 |
| 3 | 工业控制系统与私有云平台的连接需求 | 控制系统与信息系统的互联 | 视频等高带宽应用在工业领域的使用, 此类连接需要大幅提升工业以太网和通用网络技术的互通性能 |
| 4 | 私有云平台与人的连接需求 | 人通过HMI、移动设备等方式与工业IT系统的交互 | 提升HMI、SCADA、远程操控、移动设备操控等不同的软硬件人机界面的性能, 提升管理的敏捷性和效率 |
| 5 | 企业与工业公有云的连接需求 | IT系统与互联网的融合、OT系统与IT系统的融合、企业专网与互联网的融合等 | 在可靠性、带宽、时延性能、业务形态等方面提出新的要求 |
| 6 | 企业和企业的连接需求 | 不同企业信息系统互通需求, 分为两个层次：1）CRM、ERP等非核心系统的互通；2）MES等核心系统的互通 | 两类互通需求都对远程互联的可靠性、时延性能、安全性提出了新的要求 |
| 7 | 企业和用户的连接需求 | 用户需求与工业系统的实时互通是实现个性化定制的基础 | 需要工业云平台对用户定制应用的良好支撑以及对制造、物料、物流的高效协同 |
| 8 | 企业和智能产品的连接需求 | 产品和工厂的泛在连接将是预测性维护、远程维护的网络基础, 也是企业实现服务化转型的基础 | 需要重点解决广域大连接的问题, 需要物联网技术的深度应用 |