6.2.4.
Switches
A switch is a device that channels incoming data from any of multiple input
ports to the specific output port that will take the data towards its intended
destination. On a LAN, the switch determines from the physical device
address (MAC) in each incoming message frame to which output port to
forward it to and back.
Even if for WebREF both the hubs and switches are allowed, for the industrial
networking environments, a fully switched Ethernet architecture is the most
appropriate choice.
In a fully switched network, there are no hubs and therefore each network has
a dedicated segment for every node. Because the only devices on each
segment are the switch and node, the switch picks up every transmission
before it reaches another node and then forwards the data only over the
appropriate network segment. In a fully switched network, the nodes only
communicate with the switch and never directly with each other. For more
information on the network structures, see Section 6.3. Network topology .
ABB recommends for switches:
*
For small plants, ABB recommends Phoenix Contact FL SWITCH 8TX,
Ethernet switch, 8 front Ethernet ports in RJ-45 format, automatic
detection of data transmission rate of 10/100 Mbps, coupling network
segments with different transmission rates, auto-crossing function, DIN
rail mountable.
*
For medium-large plants and especially if the network has composed of
several sub-networks, ABB recommends Phoenix Contact Modular
Switch System, that can be seamlessly expanded from 8 ports up to 24
ports, offering a flexible cable outlet - either at the bottom or at the front -
depending on the requirements of the installation and location. Interface
modules are available for twisted pair, glass fiber or even cost-effective
Ethernet installations by using polymer and HCS fibers.
*
For harsh environments and/or particularly critical applications, ABB
recommends OnTime Networks switches (U200 series or R200), or
RuggedCom switches (RuggedSwitch
TM
- RS8000T or RS1600T).
6.2.5.
Router
A router is a device or, in some cases, software in a computer, that determines
the next network point to which a packet should be forwarded toward its
destination. The router is connected to at least two networks and decides
which way to send each information packet based on its current
understanding of the state of the networks it is connected to.
See Section 6.5. Communication system security for more information about
the use of standard Ethernet router and security requirements.
ABB recommendation for routers:
32
REF 542plus
Multifunctional Protection and Switchbay
Control Unit
Installation Manual for Web Interface
Installation manual
1MRS755865
