Download Installing Cabling: Procedures

Installing Cabling: Procedures
Installing Twisted-Pair Media
Topology
Ensure the topology chosen is appropriate for the transceiver in question, bus for TP/XF1250 channels and either bus or free topology for TP/FT-10 channels.
Cable Choice
Only use the transceiver manufacturers recommended cable types. Do not mix cable
types on the same segment apart for stubs for TP/XF-1250 segments.
In the case of link powered segments, ensure that the cable type chosen and the channel
link power loading delivers the correct supply voltage to link powered devices over all
temperatures.
Cable Length
Bus Topology (TP/XF-1250 & TP/FT-10)
Ensure that the cable length for the main run and stubs do not exceed the maximum
recommended length.
Free Topology (TP/FT-10)
Ensure that the maximum total length of cable does not exceed the maximum
recommended length for the cable type in question.
Extending Distances
Only use physical layer repeaters or routers to extend segment lengths. Do not exceed
one physical layer repeater per segment.
Cable Termination
Ensure that the correct segment termination method is used. Doubly terminate TP/XF1250 and TP/FT-10 segments in bus topology. Use single point termination for TP/FT10 segments in free topology. Only use the recommended termination network.
Link Power Supplies
Locate the link power supply for a segment so that the voltage to link powered devices is
kept within specification. Typically it helps to install the link power supply in the middle
of the segment.
Node Count and Distribution
For TP/XF-1250 and TP/FT-10 segments, ensure that the node count and distribution
complies with that specified in the Junction Box and Wiring Guidelines and the
transceiver users guides.
For TP/FT-10 segments using free topology, ensure that the node count and maximum
node to node distance is not exceeded.
Cable Shield Termination
When using shielded cable, for all transceiver types, terminate the shield using the RC
network shown below:
Twisted Pair
Termination Circuit
Ra
Ca
100µF
50Vmin
Cb
100µF
50Vmin
Rb
Cc
Shielded
Twisted Pair
(STP)
Shield
Grounding
Circuit
Cc = 0.1 F, 10%, Metalized Polyester,  100V
Rb = 470k, 1/4W, 5%
Ground the cable shield at least once per segment, and preferably at each node.
Grounding the shield at every node (using the shield grounding circuit shown) will assist
in suppressing 50/60Hz standing waves.
Building Entrance Protection
For inter-building communications, shielded cable and lightning protection should be
used. Full details can be found in the FTT-10A users guide.
The following diagram illustrates the concept:
Shielded Twisted Pair
Inside
Net A
Outside
1
Net B
1
Shield
2
4
Gas Discharge
Surge Protectors
(Typically <5pF)
3
2
4
3
Lightning
Protector
Protector Set
(A set is two devices (separate) or a pair
of devices in a single box).
C1
2
C1
3
Building Wall
< 300 pF = Single FTT-10A load
< 150 pF = Single LPT-10 load
-
C2
3
< 10pF
Network Isolation Rating
If the network cabling requires a specific isolation rating, do not degrade the isolation
rating by running network cabling in the same trunking or partition as other cables. Use a
separate cable tray.
Radiated Noise Sources
Avoid running network cabling in close proximity or in parallel to mains or other cabling
which may be a noise source, i.e. mains cabling carrying high current triac controlled
loads.
RF & Magnetic Fields
Do not install devices close to high RF or high magnetic fields such as linear motors
unless they are specifically designed to be installed in such an environment.
Testing
Once the segment cable and termination is in place, check the termination impedance
using an AC bridge.
Once you have physically and logically installed all devices on each channel, use a
protocol analyzer to check that the error rate is less than the acceptable limit for each
channel type and that the actual throughput matches the estimated throughput.
For link power segments, check the supply voltage at the furthest devices from the link
power supply and ensure that it meets the recommended limits when the devices are
active and in worst case current consumption conditions.
Installing Power Line Channels
Legislation
Ensure that the transceiver choice meets local legislation.
Pre-Installation Check
For commercial installations, verify that the installation is suitable for use with power
line transceivers using PLCA-xx prior to physically installing the devices. This entails
checking for injection loss, attenuation, signal-to-noise ratio, phase relationship, and error
rates between all required points in the building. Details of how to perform these tests
can be found in the relevant transceiver user’s guide. Due to the nature of the mains
network, carry out pre-installation tests over a suitable period to access the full building
characteristics over all times of day and days of the week.
For domestic installations, it may be unnecessary to perform a pre-installation check.
Node Count and Distribution
With power line networks it is very difficult to provide general numbers for node counts
and distribution as installation-specific factors affect these parameters. However, a
maximum number of 500 devices per sub station would be starting point.
Termination
In the case of unpowered media, long haul situations, or lightly loaded conditions, you
may need to include bus topology termination for the segment. Details of suitable
termination networks can be found in the relevant transceiver user’s guide.
Filtering
Due to the open nature of power line communications, you may need to filter the
incoming mains supply to suppress unwanted incoming signals or to suppress local
communication signals from escaping the building.
You may also need to filter noise from old equipment that may be in use within the
building. Commercial filters are available for this purpose. Noisy equipment should
show up during the pre-installation check.
Phase Coupling
If phase-to-phase communications are required, you will need to install some kind of
phase coupling mechanism. Details of suitable coupling circuits may be found in the
relevant transceiver users guide or Echelon power line application notes. Do not rely on
the installations natural phase-to-phase signal coupling.
Testing
Once you have physically and logically installed all devices on each channel, use a
protocol analyzer to check that the error rate is less than the acceptable limit for each
channel type and that the actual throughput matches the estimated throughput.
Domain ID
Ensure that a unique 6 byte domain ID is used for the network.
Installing RF Media
Legislation
Ensure that the transceiver choice is meets local legislation and that any necessary
licenses have been obtained.
Pre-Installation Check
You may need to perform a pre-installation check to ensure that the transceiver will work
over the required range and environment.
If possible, find other local RF sources, such as paging systems, and ensure that they will
not have any affect on the proposed installation.
Installation
Only use the manufacturer’s recommended aerial configurations.
Testing
Once you have physically and logically installed all devices on each channel, use a
protocol analyzer to check that the error rate is less than the acceptable limit for each
channel type and that the actual throughput matches the estimated throughput.
Domain ID
Ensure that a unique 6 byte domain ID is used for the network.
Other Media
Installation
Follow the transceiver manufactures specifications and advice with regard to media
length and node distribution.
Node Count and Distribution
Do not exceed the transceiver manufacturer’s recommended node count and node
distribution specifications.
Testing
Once you have physically and logically installed all devices on each channel, use a
protocol analyzer to check that the error rate is less than the acceptable limit for each
channel type and that the actual throughput matches the estimated throughput.
IP Channels
Physical installation
Do not install IP-based devices without first contacting the local IS administrator.
Ensure that the maximum distance from the device to the hub, and maximum node-tonode distances are not exceeded.
Address
Determine whether static or dynamic (DHCP) IP addressing will be used. If in doubt,
contact the local IS administrator.
Bandwidth
Ensure that, if necessary, the devices have their bandwidth clipped (QOS), consult with
the local IS administrator to see if this is necessary.
Logical Connectivity
Contact the local IS administrator to have any intermediary firewalls or routers opened
up.