Ethernet is a protocol promising as far as vendor independence is concerned, but does not eliminate the need for wiring.
The advantages of Ethernet are many: the network components have a strong tendency to low-cost Ethernet can be used as a means of transport protocol independent communication of the PLC's encapsulating the Modbus or PROPFIBUS within the TCP / IP packet, the natural feature of being multilink Ethernet provide a very strong way for future expansions, and enabled devices to which the information is sent are already integrated into Ethernet networks.
But despite these advantages Ethernet shares the disadvantage of the need to lay cable throughout the plant. It is shown that in a typical installation, the cost of cable laying exceed the cost of other equipment.
And now we can do??
Now there is a solution, wireless Ethernet, which provides the benefits of Ethernet without the need for wires, giving a robust and reliable communication.
THE WIRELESS COMMUNICATION MAY PROVIDE A ROBUST AND RELIABLE
Factors affecting the transmission of Radio
To decide which wireless technology is best for an application, it is helpful to understand the factors that affect radio transmission.
In applications inside a building, including factories, two major factors can interfere and cause signal fading rnultitrayectoria. The latter occurs when multiple copies of the radio signal to arrive at the same time, but with a different phase. This causes the signals to each other mutually se.cancelen to some extent, this results in a disappearance or reduction in signal strength.
Interference occurs when another radio frequency source generates a signal at a frequency of interest that has a field strength higher than the signal of interest. The device interferes not necessarily be another radio. In the bands used, microwave ovens and welding equipment can be sources of interference.
... Is there another factor?
A third factor affecting performance is the receiver sensitivity of the spokes, which is defined as the minimum signal strength required to receive signals at a certain rate of error. Therefore, the spokes of a better sensitivity
achieve a better reception range.
802.3 versus 802.11
802.11 (802.11 b and more recently) is a wireless Ethernet standard designed to promote interoperability between vendors of products for office networks, to promote competition - resulting in lower costs. While the goal of this rule is valuable progress in achieving interoperability has been limited.
802.3 is the standard that defines 10BaseT Ethernet (802.3u 100BaseT defined) and refers to the wired Ethernet.
Wireless devices that comply with 802.11, 802.3 meet at the point of connection to the network and comply with everything related to the protocol in the air with 802.11. The important point is that while a wireless device must comply with 802.3 to connect to the wired Ethernet, 802.11 need not meet.
INSTALLATION OF WIRELESS ETHERNET
The first step is to define the amount of data to be transmitted and the speed to be transmitted. Also, the idle period (latency) that can be tolerated. The first point will determine the required power or gain while the second will determine the amount of information that can be sent at a time. Both are inversely proportional. No matter how robust is the radio link, there will be times when the transmission is not successful and needs to be retransmitted. This retransmission is automatic and is not perceived by the network but introduces additional latency. Thus, while a higher transmission power increases when a retransmission is required, a greater amount of information increases the latency.
Next, determine the architecture of the wireless network. The number of remote devices that are connected will appear in the decision to operate in a peer-to-multipoint, multipoint or multiple links a combination of both.
This will impact the capacity of each device. When using multilink, each link will need less capacity.
The location of wireless devices also deserves attention, since the location of the field device will determine the general location of the remote device and the nearest point of interconnection to the wired network Ja. As a general rule, the antennas of the devices should be installed as high as possible without placing any obstacles between them.
and the conclusion?
Ethernet is very hard to entering the field. Wireless Ethernet offers all the advantages of Ethernet, but without laying cables. With a proper understanding of how to operate wireless devices ...
Ehternet WIRELESS COMMUNICATION YOU GIVE A ROBUST AND RELIABLE EVEN more noisy industrial environments.
