Stp991-1Ld; Attenuators - Siemens SIMATIC NET SFP Series Operating Instructions Manual

7.5.2

STP991-1LD

Properties
Transmission mode
Transmission rate
Transmission medium
Light source
Wavelength
Cable length (max.) *
Transmitter output (optical)
Receiver input
* Depending on the cable used, you can find additional information in the "Industrial Ethernet /
)
PROFINET Passive network components" System Manual, see also section "Introduction", paragraph
"Additional documentation".
7.6

Attenuators

Attenuators
Transceivers of the types LH, LH+, ELH and ELH200 are designed for long distances and
therefore send more power than they can receive.
If you establish a connection between such transceivers with a short cable length, use
attenuators. Attenuators increase the attenuation and therefore protect the receiving diode.
Select the attenuation so that the transmit power (transmitter output) behind the attenuator is
lower than the maximum received power (input power):
Transmitter output max. [dBm] - attenuator [dB] < input power max. [dBm]
Recommendation for the attenuation of the attenuator on a connection with the same
transceivers:
Transceiver type
LH
LH+
ELH, ELH200
If you have established a connection on a pluggable transceiver with a short cable length, it is
possible that the transmitter will be turned off. In this case, pull the transceiver and plug it in
again.
Transceiver SFP/SFP+/SCP/STP
Operating Instructions, 10/2019, A5E02630804-13
100Base-LX complying with IEEE 802.3
100 Mbps (Fast Ethernet)
Single mode fiber-optic cable
Class1-LASER "Eye safe"
1310 nm
26 km
)
Minimum
Maximum
Sensitivity min.
Input power max.
Attenuator
6 dB ... 12 dB
12 dB ... 20 dB
16 dB ... 24 dB
Technical data
7.6 Attenuators
-15 dBm
-8 dBm
-28 dBm
-8 dBm
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