3. Agreement details
modbus
Modbus protocol is a universal language applied to electronic controllers. Through this protocol, controllers can communicate with each other and with other devices over a network (such as Ethernet). It has become a common industry standard. With it, the control equipment produced by different manufacturers can be connected into an industrial network for centralized monitoring. Standard and open, the Modbus protocol can be used for free and at ease, without the need to pay a license fee, and without intellectual property rights infringement. Currently, Modbus is supported by more than 400 manufacturers and over 600 products. Modbus can support a variety of electrical interfaces, such as RS-232, RS-485, and can also be transmitted over a variety of media, such as twisted pair, optical fiber, wireless, etc. Modbus frame format is simple, compact and easy to understand. It is easy for users to use and simple for manufacturers to develop. Details of the agreement
PROFIBUS
The invention relates to a fieldbus technology used for factory automation shop level monitoring and field equipment level data communication and control, which can realize distributed digital control and field communication network from field equipment level to shop level monitoring
OPC-DA
In order to facilitate the exchange of data between equipment and applications of different manufacturers in the automation industry, a unified interface function is defined, which is the OPC protocol specification. The function of OPC server is to exchange data with the next machine, which contains a large number of communication procedures and data storage procedures. With OPC, you can use a unified way to access the product data of different device manufacturers. Other software vendors only need to develop programs that face the server, rather than developing different hardware drivers for different hardware devices. Reduce the workload, but also convenient to use.
The OPC Foundation provides different interface definitions, as follows:
• OPC DA (Data Access, exchange of real-time values)
• OPC A&E (Alarms & Events, exchange of alarms and events)
• OPC HDA (Historical Data Access, exchange of historical values)
• OPC XML DA (XML-based exchange of real-time values)
All of the above interface definitions are now referred to collectively as OPC. OPC is based on WINDOWS COM/DCOM interface technology to specify.
OPC UA
In order to cope with the trend of standardization and cross-platform, in order to better promote OPC, the OPC Foundation in recent years launched a new OPC standard based on the previous successful OPC application -OPC UA. The OPC UA interface protocol contains the previous A&E, DA,OPC XML DA or HDA, and uses only one address space to access all the previous objects, and is not restricted by the WINDOWS platform because it is defined from above the transport layer Scoket. Resulting in greater flexibility and security than previous OPCs.
Advantages of OPC UA:
1. A common interface that integrates all previous OPC features and information, A&E, DA,OPC XML DA or HDA
2. More open, platform independent, compatible with both WINDOWS and LINUX
3. Expanded object types to support more complex data types such as variables, methods, and events
4. Security functions are integrated at the protocol and application layers to improve security
5. Easy to configure and use
The core is different because OPC and OPC UA use different TCP layers, as follows:
OPC is based on DOM/COM, the top layer of the application layer; OPC UA is based on the TCP IP scoket transport layer.