6ES7216-2BD23-0XB8 performance parameters

6ES7216-2BD23-0XB8 Performance parameters

Each building has at least one building distribution system BD (Building distributor). All BDs are connected to the campus distribution system CD (Compus Distributor). Among them, CD can be regarded as the center of all communication, and redundancy between BDs can be applied for security reasons. In a building, the field-level FD (Floor Distributor) cabling system can be installed on several floors, and each floor can radiate a range of 2,000 square meters. Sometimes the concept of FD can be replaced by the equipment distribution system MD (Machine Distributor) because of the half position of the site is about 30 meters.
The comparison of the two images shows that AVAYA's SYSTEM MAX has a verydetailed definition of the commercial network and that the six subsystems are covered in detail. low cabling section of a commercial network.
EN50173 and ISO/IEC11801 are more suitable for the definition of industrial Ethernet physical layer cabling system FA and PA. Because as far as the current industrial Ethernet application is concerned, the cabling system is often directly from the BD to the front-end equipment. This situation must be based on the following reasons:
1. Compared with the general wiring, the horizontal wiring subsystem isautomation is currently relatively simple, without the need for patch panels (PATCH PANNEL), large logarithms, cables and other equipment.
2. SYSTEMAX's PDS system is a structured and modular wiring system, which aims to increase the flexibility and reliability of the physical layer of the building Maintainability, which is currently not needed in the FA/PA field.
3. Since there is no set of equipment for management subsystems such as patch panels, jumpers and wall sockets, etc. This also reduces interconnections, reduces the number of failures and makesthe system more reliable. However, with the penetration of IP technology in the industrial field, if the field device layer also uses a large number of IP devices (such as Sensor Actator, etc.), then it is expected that the two wiring schemes will become more and more similar, but the requirements for wiring equipment used in industrial field will be higher, and support for mobility will also be higher.

2. About industrial network topology

The topology is considering another issue at the physical layer. Topology refers to how the wires are routed in the network. A point-to-point connection is a connection between a workstation and the interface of a hub, a connection between a hub and another hub, or a connection between a workstation and another workstation connection.
Industrial Ethernet research shows that the topology described in the EN50173 standard and the ISO/IEC 11801 standard has been supplementedwith some minor modifications It can be applied to industrial environments.
And most users in industrial sites, we are more familiar with the bus connection, that is, multiple workstations share a common connection. EIA-485 or Controller Area Network (CAN) are good examples of these networks.
However, the bus topology is no longer suitable for Industrial Ethernet. While 10BASE2 and 10BASE5 are indeed bus-type coaxial cable-based Ethernet networks, they are limited to 10 Mbps half-duplex operating conditions, and because they are not included in the emergingand the commercial wiring standards TIA/EIA-568-A, their use is gradually declining.
Based on the above reasons, industrial Ethernet wiring usually adopts a star type, that is, a connection hub or a switching hub is required. Therefore, not everyone should consider using a bus-like method to connect a network such as a transmission system, although it is very simple. If you want to use industrial Ethernet, use a star, tree, or ring topology.
In a typical industrial environment, we can share from the perspective of the whole and each unitdivide eid as follows:
1. CD == Campus Distributor, i.e. the industrial estate level node
2. BD == building divider, that is say factory level node

3. FD == Floor divider, i.e. node at workshop level

4. MD == Machine divider, i.e. node at machine (equipment) level

5.MO == Machine outlet, i.e. the output node of the device
6. TO == Terminal output, that is, the terminal output node for each device output node, it connects to the network of devices in a star connection.

The access device takes over generally on a switch. For example, in Ethernet/IP, HSE, EPA and other schemes, the topological structure of full-duplex switchboard + 100Base-TX is adopted. The advantage of the switch is that it can eliminate the frequent occurrence of network conflicts by conflict domain.However, when the two upstream ports send data towant to send the downstream port, the conflict will still occur. The switch can effectively divide the shared LAN into network segments, so that each user can share the maximum bandwidth as much as possible and connect the shared Ethernet segment and LANs at different speeds. The switching technology is in the first layer of the seven-layer network model .Layer 2, the data link layer, is active and is therefore often referred to as Layer 2 switching.

The switch's forwarding of the data packet is based on Ethernet's Destination Medium Access Control (MAC). The port obtains the destination MAC address and receives the data packet by extracting the source MAC address of each data packet sent to the switch. sent. After you know the relationship between the ports, you know the relationship between the port and the MAC destination address, and the effect of the switch on improving the user's available bandwidth is obvious. Because the exchangeng on the second layer relies primarily on the MAC address to transmit frame information, an address table is built using the continuously collected data and the port from which each MAC address originates is registered and each Ethernet packet sent from the right port Sending, when a broadcast packet arrives, it must be sent to all ports of the switch. For a network consisting of only switches, it is very easy to create a broadcast storm. In addition, due to the continuous expansion of the network scale, switches and routers must be used in combination, and some defects have occurred. For this reason, the third layer and fourth layer switching technology have emerged, and a different topology connection related to the industrial environment is being not described here, the attribute is redundancy.

 Ethernet redundancy technology is not very important in general commercial applications . In the past, hubs (Hubs), switches (Switch) had been used by many people to connect various Ethernet based devices (such as PC). The hub receives a message from a particular port and then broadcasts the message to all other ports. For any message from any port, the hub will pass it to any other port. The switch can realize the routing function of the message from one port to another port, which can automatically detect the network speed of any network device. Using a " MAC Address Table" feature, switches can also identify and remember devices on the network. This intelligence avoids message conflicts and improves transmission performance, which is a huge improvement over hubs. Butdevices such as hubs and switches take simplicity and price of use into account. After the benefits, it also loses the ability to implement advanced requirements such as redundant functions.

 The later developed managed switch is relative to hubs and common switches, it has increasingly complex functions, which can usually be configured via a network-based interface. It can automatically communicate with network devices and users can also manually configure the network speed and flow control of each port. Most managed switches also providea number of advanced features such as SNMP (Simple Network Management Protocol) for remote monitoring and configuration, ports for diagnostic mapping, VLANs (Virtual Local Area Networks) for grouping network devices, priority functions to ensure priority messages pass through, etc.

 The addition of these new features makes it possible to build a redundant network using managed switches. Using a ring topology, managed switches can form a ring network. Each managed switch can automatically determine the transmission path and backup path, automatically block (block) the backup path when the priority path is interrupted.
As the requirements of industrial networks for redundant functions change, there are managed redundant switches that specifically extend functions in terms of redundancy. This type of switch offers some special functions, specially designed for redundant systems with strict stability and security requirements Optimization on .

 There are mainly the following ways to build a redundant network, STP, RSTP; loop redundancy and trunk Trunking technology.
1. STP and RSTP
STP (Spanning Tree Protocol), is a link layer protocol (IEEE 802.1 D) exists, provides path redundancy and prevents network loops from occurring. His approach is to force the backup data path to be blocked (blocked). If a path fails, the topology can be reconfigured and the link can be reconfigured by activating the backup path structure. network interruption recovery time is between 30 and 60 seconds. RSTP (Rapid Spanning Tree Algorithm, IEEE 802.1w), as an upgrade from STP, reduces network interruption recovery time to 1-2 seconds. The STP network structure is flexible, but there is a recovery speed The disadvantage of being slow. It is not applicable in many industrial environments.
2. Loop redundancy
After STP, in order to meet the strong real-time characteristics of the industrial control network, the loop connection network method was used to achieve rapid recovery of redundancy. Using this technology, the network can be made automatically within 300ms after the interruption, it can also remind the user of the disconnection phenomenon through the fault relay connection of the switch, the status display light and the SNMP setting.These can help diagnose the ringWhere is the network disconnected
There are generally three methods of loop redundancy:
* standalone standalone ring redundancy .
* Dual-machine single-ring redundancy.
* Dual-machine dual-ring redundancy.
The main advantage of double ring is that it can be connected through double channels, so as to avoid the trouble caused by a single cable fault. Double machines can also avoid the trouble caused by a single device fault problem.
3. Backbone redundancy Trunking technology
Multiple ports of different switches are set as Trunking backbone ports and are connected so that a high-speed backbone link can be formed between switches. Not only the network bandwidth ofthe backbone link is doubled, the network throughput is improved, but also Provides another function, which is redundancy function. When the backbone link in the network has problems such as disconnection, the data in the network is sent through the remaining links to ensure normal network communication. Trunking backbone network can adopt bus type And star network structure, the theoretical communication distance can be extended infinitely. Because this technology uses the method of hardware detection and data balance, the network interruption recovery time has reached a new height, and the overall recovery time can be less than 10ms.
Since redundancy is obviously the cost of equipment will increase, consideration should be given to what kind of redundancy structure should be usedapplied in accordance with project engineering needs.

The last topology question is the problem of the connection line length and connection capacity.
Commercial Ethernet has the famous 5-4-3 rule in terms of line length and connection capacity: there can be 5 network segments in the network, through 4 middle Repeater connection, but only 3 network segments can connect to the computer.
These similar rules still play a role in the industrial Ethernet environment. In fact, in industrial workshops such as the chemical industry, the problem of long connecting wires is very prominent. An important consideration when using twisted pair -based cables or optical fiber is the length of the connection. In the case of not using a repeater, the cable must consider the limit within 100m, and the optical fiber limit can reach the kilometer level. Based on the requirements From physical properties, all major industrial Ethernet solutions have clear requirements for line length and number of connectable nodes, the industry standard in this area is: ISO/IEC 11801

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