Siemens SIMATIC NET PROFIBUS - Manual (Page 85)

Configuring Networks
3-19
PROFIBUS Networks SIMATIC NET
6GK1970-5CA20-0AA1 Release 2 05/2000
Power budget for OLM/G11, G12 for a point-to-point link with the wavelength
λ
= 860 nm
Attenuation on the cable
Fiber type Attenuation
a
FOC
Cable length L
62.5/125
µ
m 3.5 dB/km 2.85 km L* a
FOC
= 10.0 dB
+
Attenuation for connectors
a
Conn
Number +
0.4 dB 1 Number *
a
Conn
0.4 dB
Attenuation caused by splices +
a
Spl
Number
0.2 dB 3 Number * a
Spl
0.6 dB
Attenuation of the transmission path a
Path
= 11.0 dB
Characteristic data of the OLM/G11, G12
maximum power coupled into 62.5/125
µ
m fiber
P
out, min
–13 dBm
Receiver sensitivity
Prec
, min
–28 dBm
Maximum permitted attenuation a
max
= P
out, min
– P
rec, min
= 15.0 dB
Link power margin a
max
– a
Path
= 4.0 dB
The transmission path can be implemented as planned.