Siemens SIMATIC NET PROFIBUS Attenuation of the transmission path, Afoc =, Number * aSpl, 15.0 dB

Models: SIMATIC NET PROFIBUS

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Configuring Networks

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

Cable length L

 

aFOC

 

62.5/125 m

3.5 dB/km

2.85 km

 

 

 

Attenuation for connectors

 

 

 

 

aConn

Number

 

0.4 dB

1

 

 

 

 

Attenuation caused by splices

 

 

 

 

aSpl

Number

 

0.2 dB

3

 

 

 

 

Attenuation of the transmission path

Characteristic data of the OLM/G11, G12 maximum power coupled into 62.5/125 m fiber

Pout, min

–13 dBm

Receiver sensitivity

Prec, min

–28 dBm

L* aFOC =

+

+

Number * aConn

+

Number * aSpl

aPath =

10.0dB

0.4dB

0.6dB

11.0dB

Maximum permitted attenuation

amax = Pout, min – Prec, min =

15.0 dB

Link power margin

amax – aPath =

4.0 dB

The transmission path can be implemented as planned.

PROFIBUS Networks SIMATIC NET

3-19

6GK1970-5CA20-0AA1 Release 2 05/2000

Page 85
Image 85
Siemens SIMATIC NET PROFIBUS manual Attenuation of the transmission path, Afoc =, Number * aSpl, 15.0 dB, Link power margin