Factors To Be Considered When Selecting Industrial Switches

Industrial Switch is a special type of computer network switch. Its design is mainly used in complex industrial environment. These switches are generally more robust and reliable than standard Ethernet switches, and can even provide more practical functions, such as support for industrial protocols, redundant power supplies, and extended temperature ranges. There are many brands and complex types of industrial switches. When selecting an industrial switch, many factors need to be considered, such as working environment, whether redundancy is required, network management and non network management, future maintenance and scalability. Generally speaking, reliability, real-time, security, compatibility and other factors should be considered when selecting an industrial switch.

1. Real time

In different application environments, the response time and jitter that the system can tolerate are quite different. Data frames in the automation network will have a certain delay in each process of forwarding from one device to another. Therefore, the first thing to consider when selecting an industrial switch is the port delay of the switch in the process of data frame forwarding.

In the standard factory automation control system, the system can tolerate a response time of no more than 10 milliseconds. In order to control the cumulative delay of data frames from the top to the bottom of the system, when selecting an industrial switch, it should be noted that the switch port delay should not exceed 10 microseconds.

2. Reliability

In the industrial field environment, reliability is undoubtedly the most important point. Factors to be considered include: resistance of equipment hardware to working environment, such as working temperature range, EMC, installation and power supply mode. Industrial switch equipment is different from commercial Ethernet equipment, and generally adopts a compact design and rail installation mode more suitable for field cabinet installation. In order to avoid equipment damage caused by rotating parts failure, hardware equipment without fan design should also be selected. In the parameter description of the product, there should be a detailed description of the working temperature range and electromagnetic compatibility. The certificate of relevant access standards shall be attached. After selecting reliable and stable hardware, pay attention to all kinds of redundancy modes that industrial switches can provide, as well as fast fault diagnosis and recovery.

3. Security

Because of the openness of Ethernet, we have to consider the factor of network security in the process of building an automation network. When selecting equipment, users should select industrial switches with VLAN function to facilitate the function division of the network. Through VLAN division, we can isolate the devices in the network by groups based on functions to avoid malicious damage or misoperation. At the same time, users can use the 802.1x function in the switch to authorize and license the devices that need to access the network, so as to distinguish between legal users and illegal users.

4. Compatibility

Industrial switches and other components of industrial Ethernet should be able to communicate using standard TCP/IP protocols. In any case, there should be no incompatibility between industrial switch equipment and commercial Ethernet equipment. Corresponding to different industrial field bus solutions, industrial switch equipment shall have corresponding capabilities compatible with them. At this stage, the ring network protocols of industrial switch components from different manufacturers are different. In order to consider expansion and compatibility, users should also choose equipment with MRP media redundant ring protocols, laying a good foundation for future network expansion. This protocol standardizes the ring network protocol, allowing different brands of equipment to be connected together to form a ring network.

5. Other factors

According to the requirements of practical applications, other common functions should be noted when selecting industrial switches. For example, QoS priority queues that distinguish different service data priorities, or port mirroring for network fault diagnosis. However, it should be noted that not all switches with more functions are necessarily suitable for each application environment. For example, the routing function often destroys the priority label and real-time performance of data transmission. The use of a large number of layer 3 switches in the control layer and even the field layer greatly increases the cost, and also destroys the application characteristics of industrial Ethernet. Users should choose appropriate functions and purchase appropriate equipment according to their needs to avoid unnecessary waste.

In the field level, the industrial switch only needs to provide port connection, and there is no need to use network equipment with complex functions. In the control layer, it is generally necessary to select a managed industrial switch that supports the ring network function to build a redundant ring network to provide an effective diagnosis mode. For the connection of each control unit, the enhanced managed industrial switch can be used to provide redundant connection and VLAN division. When it is necessary to connect with the information layer network, you should use a device with complex functions such as a layer 3 switch.

Conclusion: There is no better, only a more appropriate industrial switch. When selecting an industrial switch, in order to make the best decision according to specific needs, you need to understand your specific needs first. Different industrial switches may provide different functions. Please be sure to select an industrial switch with the required functions.