preamble
This article introduces the OPC protocol, related open source libraries, compile and build the basic environment for Qt development OPC.
Demo
OPC
OPC (OLE for Process Control) is an industrial standard for data exchange and interoperability between different devices and applications in industrial automation systems. The following is a detailed description of OPC:
Origins and Development of OPC
OPC originated in the 1990s. With the continuous development of industrial automation technology, data exchange and interoperability between devices and application software from different vendors has become an urgent problem. In order to solve this problem, OPC Foundation (OPC Foundation) came into being and launched the OPC standard. After years of development, OPC has evolved from a simple data exchange standard into a complete industrial automation communication architecture.
Core Features of OPC
- Cross-platform: OPC standards do not depend on specific operating systems or hardware platforms, and interoperability can be realized on different operating systems and hardware platforms.
- Real-time: OPC standard supports real-time data exchange, which can meet the real-time requirements of industrial automation systems.
- Security: The OPC standard provides a variety of security mechanisms, such as data encryption and authentication, to ensure the security and integrity of data transmission.
- Ease of Use: The OPC standard provides simple interfaces and protocols that allow developers to easily implement data exchange and interoperability between devices.
Architecture of OPC
The architecture of OPC consists of the following main components:
- OPC Server: The OPC server is the data source in the industrial automation system, which is responsible for collecting and storing the data from the devices and providing it to the OPC clients for access.
- OPC Client: An OPC client is a data consumer in an industrial automation system that obtains data from an OPC server and processes and analyzes it.
- OPC Interface: The OPC interface is a bridge for data exchange between the OPC server and the OPC client, which defines the format and protocol for data exchange.
OPC Application Scenarios
OPC is widely used in industrial automation, including but not limited to the following:
- Monitoring system: OPC can be used to build a monitoring system that collects and displays the operating status and parameters of equipment in real time.
- Control system: OPC can be used to build control systems to realize remote control and regulation of equipment.
- Data Acquisition System: OPC can be used to build a data acquisition system that collects real-time data from devices and stores and analyzes it.
- Historical data access system: OPC supports historical data access function, which can query and analyze the historical data of the equipment and provide decision support for optimizing production and management.
OPC UA（Unified Architecture）
With the development of industrial automation technology and the rise of the Internet of Things (IoT), the OPC Foundation introduced the OPC UA standard, which is an upgraded version of the OPC standard that adopts a service-oriented architecture and a unified data model, providing more flexible and powerful data exchange and interoperability functions.OPC UA also supports cross-platform and cross-system data exchange and remote monitoring functions, which brings wider and deeper applications in the field of industrial automation. OPC UA also supports cross-platform, cross-system data exchange and remote monitoring functions, bringing more extensive and in-depth applications in industrial automation.
OPC UA open source library
There are two open source libraries based on C/C++ as follows:
open62541
- Key Features: A lightweight, embedded C/C++ OPC UA implementation.
- Programming language: C/C++.
- Features: supports cross-platform; follows the Mozilla Public License v2.0 license; provides a complete implementation of the OPC UA stack, including server, client, subscription and publishing features; easy to integrate and extend; detailed documentation and tutorials.
FreeOpcUa
- Key Features: A full-featured C++ OPC UA server and client library.
- Programming language: C++.
- Features: follow the LGPL-3.0 license; support for data change events, state change events and filtering features; provide basic authentication and certificate handling features; support for automated code generation; detailed documentation and sample code; recently added features such as Python bindings and automation tools.
open62541
summarize
open62541 is an open source implementation of the OPC UA (OPC Unified Architecture) protocol stack. written in a generic subset of the C99 and C++98 languages, open62541 works with all major compilers and provides the tools necessary to implement dedicated OPC UA clients and servers or to integrate OPC UA-based communication into existing applications. The open62541 library is platform-independent, all platform-specific functionality is implemented via exchangeable plug-ins, and plug-in implementations are provided for major operating systems.
Functional Features
- Open Source Free: open62541 is licensed under the Mozilla Public License v2.0, so the open62541 library can be used in non-open source projects. Only changes to the open62541 library itself need to be released under the same license. The plugin, as well as the server and client examples, are public domain (CC0 license) and can be reused under any license without having to release changes.
- Cross-platform: open62541 supports a variety of operating systems and platforms, including Windows, Linux, macOS, etc., with good portability.
- High performance: open62541 adopts event-based architecture and asynchronous I/O mechanism, which has very good performance and scalability and is suitable for application scenarios with high real-time requirements.
- Security: The OPC UA protocol provides a variety of security mechanisms, including authentication, encrypted transmission, etc. open62541, as an implementation of the OPC UA protocol stack, also inherits these security features.
- Extensibility: open62541 supports flexible data models and service extensions that can be customized and extended according to specific needs. It also supports plug-in development, which can easily add protocol extensions, authentication mechanisms, encryption protocols and other functions.
application scenario
The open62541 can be used in a variety of industrial automation and IoT scenarios, for example:
- Industrial control system: to realize data exchange and control between different devices, and to realize the integration and optimization of industrial automation system.
- Intelligent Manufacturing: Realize data sharing and collaboration between equipment to improve production efficiency and quality.
- Intelligent buildings: to realize the monitoring and management of building equipment, and to improve the efficiency of energy use and comfort.
- IoT application: realizing data transmission and communication between IoT devices, realizing application scenarios such as smart home and smart city.
Source Code Download
Compile open62541
Step 1: Download and unzip
Step 2: Configure configure
Use cmake to configure it:
The configuration went through without a hitch, remember to configure the path to install install, and then you also need to reconfigure it to take effect:
Step 3: Generate project Generate
At this point, the use of CMake is complete.
Step 4: Compilation
Start compiling:
Compilation completed
Step 5: Installation
Step 6: Check the installation directory
.a is the static library way, you can configre configure it as a dynamic library way, whatever here.
Modified to release version, only 1.2MB now:
modularization
Demo Source Code
QString OpcClientManager::getVersion()
{
UA_Client *client;
LOG << client;
client = UA_Client_new();
LOG << client;
UA_ClientConfig_setDefault(UA_Client_getConfig(client));
return QString(UA_OPEN62541_VERSION);
}
Engineering Templates v1.0.0
fig. make a career out of it
Pitfall 1: Can't find the library
concern
Function Error
rationale
This is missing some windows base libraries.
tackle
fill in (blanks, gaps etc)
LIBS += -lws2_32
