13
6650-2260
Network installation
The LRW-112 is installed in the network as any standard LON router.
The FO-10 standard channel may be used when creating a channel object.
Note:
LRW-112 and LRW-102 cannot be used in the same fibre optic network. It is pos-
sible to connect LRW-112 and LRW-102 via the LON interface.
Status interface
This interface enables supervision of fibre optic link state.<8 ohm means that status is OK.
The fault state will be set if:
Local or remote fibre link errors exist.
…
The unit is out of service, e.g. no power supply.
…
LON Channel delay
On the fibre channel the devices are attached in a daisy-chain fashion. The signal path is
through each device, that is the packet passes through each device on its way. The signal
is regenerated each time it passes through a device, thus very long distances network
could be built.:
The time of propagation depends on the distance and the number of devices to
pass through. The propagation delay affects the channel communication parameters.
By default the LRW-112 has been programmed with communication parameters suitable
for a relative small to medium fibre network that follows the below equation:
Fibre distance (m) / 200 + Number of units < 72
For example the above equation would allow four LRW-112 units to use maximum fibre
optic cable length of 13.6 km (8.5 mi).
For larger networks the LRW-112 can be programmed with communication parameters
compensating for longer propagation delays. With parameters for large network the
following equation can be used.
Fibre distance (m) / 200 + Number of units < 576
For example, the above equation would allow eight LRW-112 units to use maximum fibre
optic cable length of 13.6 km (8.5 mi). Observe however that the maximum allowed fibre
length between two LRW-112 units is 20 km (12.4 mi) (using singlemode cable) depend-
ing on the performance of the fibre optic transmitter and receiver.
See page 15 for power budget tables.
It is recommended to use a LON
®
protocoll analyser to verify network perfomance dur-
ing high peak channel access.
The above discussion considers the limitation in maximum distace due to protocoll
parameters involving media access and network idle detection. As with all fibre optic
products, the maximum distance is also dependent on the over all power budget, see
page 15.
