Specifications

7SR242 Duobias Data Communications
©2010 Siemens Protection Devices Limited Chapter 4 Page 8 of 43
The following table can be used to record budget calculations:
A Launch power
dB
B Fibre Type
C Loss (dB/km)
dB/km
D Length
km
E Total fibre loss (CxD)
dB
F No. of Splices
G Loss at each splice
dB
H Total loss at splices (FxG)
dB
I No. of connectors
J Loss per connector
dB
K Total loss at connectors (IxJ)
dB
L Total losses (E+H+K)
dB
M Receive power budget (A-L)
dB
N Safety Margin
dB
O Device Receive Sensitivity
dB
There are two optional fibre optic ports, Com3 and Com4, and when fitted the associated settings are available in
the Data Communication menu. To allow communication using either or both of these ports the relay settings
must be changed, via the fascia, in accordance with the method of connection and master device.