OPC UA: New Generation Technology for Standard Industrial Communication

PACTECH / ICPDAS (EC17W35_02, by Sun Chen)

The OPC Unified Architecture (OPC UA), released in 2008, is a standard technology for industrial automation communication. It is a platform that integrates all technology standards such as OPC DA, HA, and AE, etc. It features reading and writing real-time data, accessing historical data, and event/warning publishing functions.

By using reliable cross-platform architecture, OPC UA no longer needs to rely on the Windows platform as OPC DA used to be. The OPC products can now be deployed in different environments, such as micro-controller or in the IT engine room completing the communication and interoperability between the OPC data and related events. In addition, security is improved as it also provides user account and authority validation between the Server and Client to protect the privacy of the service and the security of message transmission.

The advantage of using OPC UA technology

OPC is designed to play an intermediary role between automation hardware providers and software developers. Based on the standard OPC interface, devices and software can communicate with each other so that service providers can focus on their specialties without worrying about issues related to the communication protocol between the hardware and the software when performing data transmission.

The latest OPC UA technology includes the following features that provide more options to the users.

1. Guaranteed seamless integration with conventional OPC service products

The UA data model is compatible with the conventional OPC thanks to a “Wrapper” that allows the UA program to be packaged in Microsoft COM technology. Consequently, early adopters do not need to upgrade their conventional OPC as the “Wrapper” allows connections to newly added OPC UA services.

2. Break the limitations of conventional OPC

Functional equivalent: all classic specifications for the COM OPC are included on the UA.

Platform independence: can be deployed on the embedded controller or in the cloud-based engine room, etc.

Security: provides encryption, authentication, and validation between users and services.

Scalability: add new functionality without affecting current applications and programs.

Full-range information modeling: can be used to define complex information modeling.

3. Reliable Design

The design of the UA ensures the arrival sequence of the data and the content validation when performing message transmission which helps decision making for back-end processing and enhances data accuracy for the data logger software. This is perfect for implementation in industrial production or service system applications where idle times are imperative. By using redundant mode, the OPA UA provides redundancy support so that the system can be resumed in real time or within a short time.

4. Collaborative Technology Foundations

The OPC Foundation works with various technology foundations to incorporate data models from a variety of technologies into the OPC UA, means that interoperability in technology can be achieved while also improving applications related to industrial automation, production processes, ERP, sales enterprises, building automation, security, and smart grid industries, etc. For example, foundations related to field devices, such as the FDT Group, the Fieldbus Foundation, the HART Communication Foundation, PROFIBUS & PROFINET International, and foundations related to building automation, such as the BACnet Interest Group and the ISA95 of the International Automation Association, etc.

ICP DAS OPC UA Solution

The UA-5231 is the first data acquisition controller developed by ICP DAS which can be integrated with the OPC UA Server, MQTT services, and other data communication protocols. Based on the advantages of the RISC-based CPU architecture, compact size and low power consumption, the UA- 5231 can be applied to a variety of field environments. Applying the OPC UA allows integration of ICP DAS I/O products with third-party devices, and then data information can be imported to the backend SCADA, cloud or other decision-making or data logging system, thereby satisfying the reliability, interoperability and security needs of the industrial automation system while meeting the requirements of the smart internet.

UA-5231

■ OPC UA Server and MQTT Client Service
■ Embedded MQTT Broker
■ AM3354, 1 GHz
■ 256 MB RAM and 512MB Flash
■ Linux kernel 3.2.14
■ Real-Time Capability
■ 64-bit Hardware Serial Number for Software Protection
■ Supports Redundancy and PID
■ 10/100/1000 Mbit/s Ethernet Port
■ 4 Serial Ports (RS-232/RS-485)
■ Wide Operating Temperature Range: -25 to +75° C

UA-5231 Software Features

With the Web-based User Interface, the users can log in and configure the controller via a web browser on a mobile device or PC.

The IEC 62541 standard OPC UA Server is certified by the OPC UA Server OPC Foundation, which helps to integrate onsite devices and actively upload data to the application systems without worrying about cross-platform issues.

Implement OPC UA Server Redundancy. The ICP DAS OPC UA Client product can provide redundancy functionality for the Server to enhance the reliability of the system.

The PID function can be used to combine remote I/O devices to simulate the PID control system when computing control solutions are required onsite.

The Modbus TCP/RTU Master module can be used to connect to all-kinds of standard Modbus TCP/RTU Slave devices via the RS-485, RS-232, or Ethernet ports on the controller. Therefore, scalability and flexibility can be provided when building a system that meets the various requirements of a wide range of applications.

The MQTT Broker is compliant with the MQTT v3.1.1 protocol and supports MQTT message distribution management. Users do not need to build a Broker system when using MQTT communications.

The MQTT communication function allows communication between IoT devices and the OPC UA system. The UA-5231 then conducts data acquisition and management function while, at the same time, data from devices managed by the UA-5231 controller can also be converted and published to the IoT system.

Application Architecture:

– Modbus I/O convert to/from OPC UA

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– Modbus I/O convert to/from MQTT

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• MQTT convert to/from OPC UA

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– MQTT convert to/from MQTT

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Summary

With the arrival of the Industry 4.0 era, a smart factory requires real-time response and automated production. The ICP DAS UA-5231 controller can help to fulfill the integration of a wide range of physical or virtualized functionalities. The UA-5231 is a versatile intermediary control system. At the lower end, it can integrate sensors, onsite devices and IoT applications, and at the upper end, it can integrate project management, manufacturing and other management applications.

By using the UA-5231 controller, factories and enterprises can:

1. Create the web-based vertical integration of both the upstream and the downstream system.
2. Integrate onsite data in the back-end system for further analysis.
3. Horizontally connect each subsystem.

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