Siemens SIMATIC SCP Series, Руководство по эксплуатации

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7.5.2 STP991-1LD
Properties
Transmission mode
100Base-LX complying with IEEE 802.3
Transmission rate 100 Mbps (Fast Ethernet)
Transmission medium Single mode fiber-optic cable
Light source Class1-LASER "Eye safe"
Wavelength 1310 nm
Cable length (max.) *
)
26 km
Transmitter output (optical) Minimum -15 dBm
Maximum -8 dBm
Receiver input Sensitivity min. -34 dBm
Input power max. -3 dBm
*
)
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 Attenuator
LH 6 dB ... 12 dB
LH+ 12 dB ... 20 dB
ELH, ELH200 16 dB ... 24 dB
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.
Technical data
7.6 Attenuators
Transceiver SFP/SFP+/SCP/STP
Operating Instructions, 12/2017, A5E02630804-11
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