GE Industrial Solutions POWER LEADER PMCS Network Architecture Guide - Manual (Page 23)

Power Management Control System
Chapter 2 – Network Design
13
NOTE for EPM 7700 and 9450Q and 9650Q: The EPM
7700 with Xpress card directly uses either of two types of
Ethernet physical media that must be specified when
ordering the meter, 10Base-T, or 10Base-FL. EPM 9450Q
and EPM 9650Q must be ordered with 10 Base-T Ethernet
Option. The meters operate in a 10 Mbps system.
10Base-T is specified when twisted pair is used and 10Base-
FL is specified where fiber optic cable is used. While media
converters are available to allow the use of both twisted
pair and fiber optic cable in the same LAN, and can be
used to extend the length of the LAN, they are beyond the
scope of this discussion.
CAUTION: The recommended installation
practice is to implement optical fiber for
connections between buildings to provide
electrical isolation. This eliminates harmful
ground loops caused by differences in the
ground potential between structures.
CAUTION: Data line surge protection is
recommended for network components such as
hubs, computers, or modems connected to IEDs
with copper wire, especially installations where
the data communication cable is exposed (i.e.,
not encased in conduit) or runs parallel to power
conductors. PMCS IEDs are routinely installed in
areas exposed to heavy electromagnetic fields
(EMF), which can induce damaging surges in
data communication lines. Data line surge
protection is not required for fiber optic
connections.
10Base-T specifications and rules
10Base-T Ethernet uses CAT 3, 4 or 5 twisted pair cable,
depending on the installation.
Maximum/Minimum length of segments
For a 10Base-T LAN, the maximum length of a segment is
100 meters (328 ft). The minimum length of any cable is
2.5 Meters or about 8 ft. This minimum length is of
particular concern when a device is located in close
proximity to the hub.
Maximum number of segments
A 10Base-T LAN can consist of up to 5 segments using 4
repeaters. However, only three of these segments can have
devices connected.
Maximum number of devices
A 10Base-T LAN can have a maximum of 1024 devices
connected.
Use of repeaters, routers, bridges, gateways, etc.
Repeaters may be used to connect LAN segments and do
not determine the boundaries of the LAN. They are used
to extend the LAN beyond a single segment. Routers,
bridges and gateways may be used to connect the LAN to
other LANs or to a WAN.
10Base-FL specifications and rules
Maximum/Minimum length of segments
For a 10Base-FL LAN, the maximum length of a segment is
2000 meters (6500 ft). The minimum length of any cable
is 2.5 Meters or about 8 ft. This minimum length is of
particular concern when a device is located in close
proximity to the hub.
Maximum number of segments
A 10Base-FL LAN can consist of up to 5 segments using 4
repeaters. However, only three of these segments can have
devices connected.
Maximum number of devices
A 10Base-FL LAN can have a maximum of 1024 devices
connected.
Use of repeaters, routers, bridges, gateways, etc.
Repeaters may be used to connect segments and do not
determine the boundaries of the LAN. They are used to
extend the LAN beyond a single segment. Routers, bridges
and gateways may be used to connect the LAN to other
LANs or to a WAN.