Industrial Ethernet cabling and fault Maintenance

Industrial Ethernet cabling and fault Maintenance

The industrial environment is worse than the general environment. At least the vibration, moisture, and temperature are worse than the general environment. Industrial Ethernet requires more professional knowledge and practical experience. If you are installing or using an industrial Ethernet (Industrial Ethernet switch), you must understand the Five Points of cabling, signal quality, grounding circuit, switch, and communication. Otherwise, faults may easily occur, increase maintenance costs.

Wiring problems

Like all networks, the advantages and disadvantages of cables directly affect the advantages and disadvantages of Industrial Ethernet. In addition to high electromagnetic interference (EMI), industrial environments often have a certain level of temperature, dust, humidity, and other factors that are not common in the home and office environments.

So how do I select a cable? In the office, commercial cables, such as class 5 cables, are suitable for 10 MB networks, while class 5e cables are suitable for MB networks. According to ANSI/TIA-1005 standards, type 6 cables or better cables can be used to connect hosts or devices in industrial environments.

Category 6 cables Support 1 GB network in the range of 100 meters and 10 Gb network in the range of 55 meters. The 6e Cable supports 10 Gb network in the range of 100 meters.

Compared with Category 5 and category 5e cables, Category 6 cables are not susceptible to crosstalk and external EMI noise. Industrial Ethernet cables are designed to withstand physical erosion of cables in more harsh industrial environments. Make sure that the RJ45 interface and socket can also be of Class 6 levels when installing 6 types of cables. It is best to use a pre-prepared plug-in cable for short-distance cabling and install the connector in the factory. Use a socket for long-distance cabling.

Cable, shield, and ground Circuit

Some applications need to be shielded, but if the shielding cable is improperly installed, it will be counterproductive.

When the protection casing is exceeded, the performance of the shielded ethernet cable in the EMI environment is better. Good grounding is the key to using shielded cables. A grounding reference point is the key. Multiple grounding Connections form a grounding circuit, and noise is introduced into the cable when the potential at different grounding connections is different.

The grounding circuit will cause great damage to your network. To solve this problem, only use the ground RJ45 interface at one end of the cable, the other end uses an insulated RJ45 interface to eliminate the possibility of a ground loop.

If the ethernet cable and the power cable are crossly cabled, the cross angle is quite exquisite. Separate the parallel ethernet cable from the power cable by at least 8 to 12 inch. If the voltage is high or the parallel column distance is long, the distance between them should be larger. If the ethernet cable is laid in a metal groove or casing, the adjacent groove or casing must be connected together for electrical continuity.

Generally speaking, ethernet cables should be kept away from equipment that can produce EMI, such as motor, motor control equipment, lighting equipment, and charged conductor. On the panel, the ethernet cable and connector must be at least 2 inch apart. Follow the recommended bending radius when the cable is away from EMI interference sources.

Vswitch VS. Hub

In short, do not use hubs in Industrial Ethernet environments. A hub is only a multi-port repeater. If the hub is excluded, only the managed and non-managed switches are available. A managed switch is better. Of course, its price is more expensive than a non-managed switch.

Each device on the network has a unique identifier, which is what we call the MAC address. This is the key for a switch to have better recognition capability than a hub.

When a vswitch is powered on, its initial performance is no different from that of a hub. It broadcasts all the communication content, however, as devices on the network transmit information on different ports of the switch, the switch starts to monitor the communication content and identify which MAC address is related to which port, then, make an identifier in the MAC address table. Once the switch finds that the MAC address of the device is connected to a specific port, it monitors the information pointing to that MAC address and then sends the information only to that specific address.

There are three communication types for Industrial Ethernet networks. Point-to-Point unicast communication, one-to-many multicast communication, and one-to-all-node broadcast communication.

After the MAC address table of the vswitch is created, the management switch and the non-management switch have no different processing methods for unicast communication and broadcast communication. Generally, the broadcast frequency is controlled to 100 broadcasts per second at a bandwidth of MB. For any network, broadcast communication will exist more or less. One example is to print that the server periodically provides broadcast notifications on the network.

Snoop: not just listening

One major difference between managed and non-managed vswitches is the way they handle multicast communication. Multicast Communication usually comes from smart devices mounted on the factory process network. It adopts connection-oriented technology based on the manufacturer/user model. In this case, the connection is only the relationship between two or more nodes on the network.

To receive group information, the device must join the multicast communication group. All members in the group can receive data. If you only send data to a group, you do not need to become a group member. In the manufacturer/user model, the main problem of multicast communication is that as the number of group members increases, the communication information increases exponentially. In this case, you need to use a managed switch.

The managed switch can enable the Internet Group Management Protocol (IGMP) Snoop function. It works like this. When the IGMP Snoop function is enabled, it sends a broadcast communication to determine members in any multicast group. With this information and the created MAC address table, the management switch can send multicast communication only to members in the multicast group. A non-managed switch processes multicast data in the same way as broadcast data, and sends the data to each node.

If the network uses the manufacturer/user technology or multicast communication, the managed switch is the best choice for money.

Mirror port and troubleshooting

There are many other reasons to consider using managed switches. Such vswitches generally provide the Fault Log function, which can control the speed of each port and provide redundant settings and port mirroring. These out-of-quota capabilities can ensure more accurate control of network behavior and play a very valuable role in troubleshooting. We know that faults cannot be avoided for some nodes on the network.

When there is a problem with network performance, you must first check the switch, although for most network performance problems, the switch is rarely the core of the problem. A switch is the most likely node in the system. Its working rate is usually 10 to 50 times the working rate of other network components.

Although there is always a good software that can help you troubleshoot network faults, most of these software can only see broadcast communication and multicast communication. This is actually quite reasonable because many performance problems are usually caused by unrestricted multicast communication or excessive broadcast communication. If you need to check unicast communication for some reason, the port image is the only way.

If there is no multicast communication on the network, it is no problem to use an unmanaged switch. On a small, simple network with few devices, many people use non-managed switches.

Sometimes these two types of switches can be used in combination, and some remote devices can be mounted on non-managed switches to provide unified feedback to managed switches.

For networks with a large number of nodes, if the cost is not a key factor, choose a managed switch. It is indeed a wise choice to come later.