1. Harsh industrial site environment

Since Ethernet was designed at the beginning, it was not based on industrial network applications. When it is applied to industrial sites, facing harsh working conditions, serious inter-line interference, etc., these will inevitably cause its reliability to decrease. In a production environment, industrial networks must have good reliability, recoverability, and maintainability. That is to ensure that when any component in a network system fails, it will not cause the application, operating system, or even the network system to crash and paralyze.

Industrial Ethernet switches are designed to take into account the complex conditions of the industrial site, so that they can be more adapted to the industrial environment and play the role of industrial-grade switches.

The environment of the industrial site is worse than the ordinary environment, at least in terms of vibration, humidity, and temperature, ordinary switches are not designed to withstand the various situations that appear in the industrial environment, ordinary switches cannot work in this harsh environment for a long time, and they are often prone to failures, which increases maintenance costs. It is generally not recommended to use commercial switches in an industrial environment. In order to enable the switch to be used in this harsh environment, a switch that can adapt to this environment is produced. The reliability of the industrial-grade switch includes power failure, port interruption, relay output alarm, redundant dual DC power input, active Circuit protection, automatic circuit breaker protection for over-voltage and under-voltage, (reliability varies slightly depending on the model).

The functional difference mainly refers to: industrial-grade switches are closer to industrial network communication in function, such as interconnection with various fieldbuses, equipment redundancy, and equipment real-time, etc. The difference in performance is mainly reflected in the adaptation to the external environmental parameters. In addition to many severe environments such as coal mines and ships, the industrial environment also has special requirements in terms of EMI (electromagnetic compatibility), temperature, humidity, and dust resistance. Among them, the influence of temperature on industrial network equipment is the most extensive.

2. The Ethernet network load is heavy

Because the MAC layer protocol of Ethernet is CSMA/CD, this protocol makes conflicts on the network, especially when the network load is too large, more obvious. For an industrial network, if there are a large number of conflicts, the data must be retransmitted many times, which greatly increases the uncertainty of the communication between the networks.  In an industrial control network, this uncertainty from one place to another will inevitably lead to a decrease in system control performance.

3. Strict real-time performance of industrial data

In industrial control systems, real-time can be defined as the measurability of the system’s response time to an event. After an event occurs, the system must respond within a time frame that can be accurately foreseen. However, the industry has very strict requirements for real-time data transmission, and data update is often completed within tens of ms. And also because of the CSMA/CD mechanism that exists in Ethernet, when a conflict occurs, the data must be retransmitted, which can be tried up to 16 times. Obviously, this conflict resolution mechanism comes at the cost of time. And once there is a disconnection, even if it is only a few seconds, it may cause the entire production stoppage or even equipment and personal safety accidents.

Well, the above content is shared by JHA TECH on why industrial ring network switches must be used in industrial sites? A detailed introduction to this issue, I hope it will be helpful to everyone!