Common Hardware Faults and Troubleshooting Methods of Industrial Ethernet Switch

Affected by the power supply, indoor temperature, indoor humidity, electromagnetic interference, static electricity and other computer room environment, the common hardware faults of industrial ethernet switch mainly refer to the faults of power supply, backplane, module, port and other components of industrial ethernet switch, which can be divided into the following categories:

(1) Power failure:

The power supply is damaged or the fan stops due to unstable external power supply, aging of power supply line or lightning stroke, so it can not work normally. The damage of other parts in the Industrial Switch due to the power supply also often occurs.

If the power indicator on the panel is green, it means it is normal; If the indicator is off, it indicates that the industrial switch is not powered normally. Such problems are easy to find, solve and prevent.

For this kind of fault, we should first do a good job in the supply of external power supply. Generally, independent power lines are introduced to provide independent power supply, and voltage regulators are added to avoid instantaneous high-voltage or low-voltage phenomenon. If conditions permit, UPS (uninterruptible power supply) can be added to ensure the normal power supply of industrial switches. Some ups provide voltage stabilizing function, while others do not. Pay attention to the selection. Professional lightning protection measures shall be set in the machine room to avoid the damage of lightning to the industrial switch. Now there are many professional companies engaged in lightning protection engineering, which can be considered when implementing network wiring.

(2) Port failure:

This is a very common hardware failure. Be careful when plugging in and out the connector, whether it is the optical fiber port or the RJ-45 port of twisted pair. If the optical fiber plug is soiled carelessly, the optical fiber port may be polluted and normal communication may not be possible. We often see that many people like hot plug connectors, which is theoretically possible, but it also inadvertently increases the failure rate of the port. Careless handling may also cause physical damage to the port. If the size of the crystal head purchased is too large, it is also easy to damage the port when inserting into the industrial switch. In addition, if a section of the twisted pair connected to the port is exposed outdoors, in case the cable is hit by lightning, the connected industrial switch port will be damaged or more unpredictable damage will be caused.

Generally, a port failure is the damage of one or more ports. Therefore, after troubleshooting the computer connected to the port, you can judge whether it is damaged by replacing the connected port. In case of such failure, the port can be cleaned with alcohol cotton ball after the power is turned off. If the port is indeed damaged, it can only be replaced.

(3) Module failure:

Industrial ethernet switch is composed of many modules, such as stacking module, management module (also known as control module), expansion module, etc. The probability of failure of these modules is very small, but once there is a problem, it will suffer huge economic losses. Such failures may occur if the module is plugged in and out carelessly, or if the industrial switch is collided during handling, or if the power supply is unstable.

Of course, the three modules mentioned above have external interfaces, which are easy to identify. Some can also identify faults through the indicator light on the module. For example, there is a flat trapezoidal port on the stacking module, or there is an interface similar to USB on some industrial switches. There is a console port on the management module, which is used to establish a connection with the network management computer to facilitate management. If the expansion module is connected by optical fiber, there will be a pair of optical fiber interfaces.

When troubleshooting such faults, first ensure the normal power supply of industrial switches and modules, then check whether each module is plugged in the correct position, and finally check whether the cables connecting the modules are normal. When connecting the management module, we should also consider whether it adopts the specified connection rate, whether there is parity, whether there is data flow control and other factors. When connecting the expansion module, you need to check whether it matches the communication mode, such as full duplex mode or half duplex mode. Of course, if the module is confirmed to be faulty, there is only one solution, that is, contact the supplier immediately for replacement.

(4) Backplane failure:

Each module of the industrial switch is plugged into the backplane. If the environment is humid, the circuit board is short circuited due to moisture, or the components are damaged due to high temperature, lightning and other factors, the circuit board will not work normally. For example: poor heat dissipation performance or too high ambient temperature leads to the increase of temperature in the machine, resulting in the burnout of components.

Under the condition of normal power supply from the external power supply, if all internal modules of the industrial switch cannot work normally, the backplane may be broken. In this case, even the electrical maintenance engineer may have nothing to do. The only way is to replace the backplane.

(5) Cable failure:

In fact, in theory, this kind of fault does not belong to the fault of industrial switch itself, but in practical use, cable fault often leads to the failure of industrial switch system or port, so this kind of fault is also classified as hardware fault of industrial switch. For example, the connectors are not connected tightly, the order of cables is wrong or not standardized, the cables should be connected with cross lines, but straight lines are used, the two optical fibers in the optical cable are staggered, and the wrong line connection leads to network loop, etc.

However, in the process of actually managing the network, some detailed factors are often beyond our control. The troubleshooting of network faults caused by some insignificant factors also takes some effort. So, how should we troubleshoot?

1. Exclusion method

When we face the fault phenomenon and analyze the problem, we have unconsciously learned to use troubleshooting to determine the direction of the fault. This method refers to listing all possible faults as comprehensively as possible according to the observed fault phenomena, and then analyzing and eliminating them one by one. The principle of from simplicity to complexity should be followed in the elimination to improve efficiency. This method can deal with all kinds of faults, but maintenance personnel need to have strong logical thinking and have a comprehensive and in-depth understanding of switch knowledge.

2. Contrast method

The so-called comparison method is to use the existing industrial switch of the same model and can operate normally as the reference object to compare with the fault switch, so as to find out the fault point. This method is simple and effective. The disadvantage is that sometimes it is not easy to find a switch with the same model and configuration.

3. Replacement method

Replacement method refers to the method of using normal industrial ethernet switch components to replace possible faulty components, so as to find out the fault point. It is mainly used for hardware fault diagnosis, but it should be noted that the replacement parts must be similar switches of the same brand and model.