Optical Budget Calculation For Serial Communication With Lon - ABB REQ650 Commissioning Manual

1MRK 505 385-UEN A
7.2
Breaker protection REQ650 2.2 IEC
Commissioning manual
Establishing connection and verifying the LON communication
• The node addresses of the other connected IEDs.
• The network variable selectors to be used.
This is organized by LNT.
The node address is transferred to LNT via the local HMI by setting the parameter
ServicePinMsg = Yes. The node address is sent to LNT via the LON bus, or LNT
can scan the network for new nodes.
The communication speed of the LON bus is set to the default of 1.25 Mbit/s. This
can be changed by LNT.
Optical budget calculation for serial communication
with LON
Table 9: Example
Maximum attenuation
4 dB/km multi mode: 820 nm - 62.5/125 um
0.3 dB/m plastic: 620 nm - 1mm
Margins for installation, aging, and so on
Losses in connection box, two contacts (0.75 dB/contact)
Losses in connection box, two contacts (1dB/contact)
Margin for repair splices (0.5 dB/splice)
Maximum total attenuation
Section 7
Distance 1 km Distance10 m
Glass Plastic
-11 dB - 7 dB
4 dB -
- 3 dB
5 dB 2 dB
1.5 dB -
- 2 dB
0.5 dB -
11 dB 7 dB
M11737-4 v2
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