What To Pay Attention To When Selecting Industrial Switches

Issues to be noted in switch selection:

1, Reliability

In industrial environments, reliability is undoubtedly the most important factor. Industrial automation networks can provide more reliable communication links by improving the hardware conditions and network structure of network equipment. From a hardware perspective, we need to consider factors such as the hardware's tolerance to the working environment, such as operating temperature range, EMC electromagnetic compatibility, installation, and power supply method.

Industrial Ethernet devices differ from commercial Ethernet devices in that they generally adopt a compact design and rail installation method that is more suitable for on-site cabinet installation. To avoid equipment damage caused by rotating component failures, hardware equipment with no 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. And accompanied by proof of relevant admission standards.

Certification and standards that relevant industry organizations can provide. In on-site application environments in different industries, it should be noted that the selected equipment should have certification provided by the corresponding industry organization.

2, Real time performance

In the field of automation earlier, Ethernet was not recognized because of its poor real-time characteristics. With the emergence of switched Ethernet, full duplex communication greatly improves the real-time performance of Ethernet. On the basis of providing reliable connections, good real-time performance of industrial Ethernet devices is equally important. The response time and jitter that the system can tolerate vary greatly in different application environments. Data frames in automated networks experience a certain delay every time they are forwarded from one device to another.

Therefore, when choosing an industrial Ethernet switch, the first thing to consider is the port delay of the switch during the data frame forwarding process. In a 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 a switch, it should be noted that the switch port delay value should not exceed 10 microseconds.

If applied in the field of motion control, the requirements for real-time characteristics of the system are greatly increased, with a response delay requirement of less than 1 millisecond and a jitter error not exceeding 1 microsecond. At this point, the range of available switches is reduced, and it is best to choose an isochronous synchronous real-time switch with ProfinetIRT function. In cases where the IRT function cannot be used, at least devices with IEEE1588 precise synchronization function should be selected to achieve soft real-time through clock synchronization.

3, Compatibility and Security

The biggest advantage of industrial Ethernet compared to fieldbus is its openness and transparency. Industrial Ethernet switches are compatible with conventional Ethernet communication and can adapt to various special industrial Ethernet standards. Firstly. Industrial Ethernet switches and other components of industrial Ethernet should be able to communicate using the standard TCP/IP protocol. Under no circumstances should there be any incompatibility issues between industrial Ethernet devices and commercial Ethernet devices. Secondly, corresponding to different industrial fieldbus solutions, industrial Ethernet devices should have corresponding capabilities and compatibility with them.

4, Other

According to the actual application requirements, when choosing an industrial Ethernet switch, it is also necessary to pay attention to other commonly used functions. For example, QoS priority queues that differentiate between different business data priorities, or port mirroring functions that facilitate network fault diagnosis. However, it should be noted that switches with more functions are not necessarily suitable for every application environment. For example, routing functions often disrupt the priority labels and real-time performance of data transmission. The use of a large number of three-layer switches in the control layer and even the field layer greatly increases costs, while also damaging the application characteristics of industrial Ethernet. Users should choose appropriate features and purchase appropriate devices according to their needs to avoid unnecessary waste.

During the process of selecting a switch, users should also choose appropriate twisted pair or fiber optic interfaces based on basic requirements such as transmission distance and bandwidth. When connecting video terminals, wireless base stations, and other devices, switches with PoE Ethernet power supply function can be selected for easy wiring. These requirements are quite intuitive, just pay attention to the corresponding indicators when selecting.

In addition, if encountering mobile devices or special situations where cable laying is not convenient, users should also consider using wireless industrial Ethernet devices. Different from wired networks, this requires consideration of other complex factors that need to be discussed separately. Based on the above suggestions, we discussed the application characteristics of industrial Ethernet switches and the types of devices used in different situations. Due to the significant differences in device naming conventions among various brands of industrial Ethernet switches, it is best to consult the supplier before purchasing to select a suitable product.