The Receive Section; The Transmit Section - Siemens SWT 3000 Equipment Manual

MW Measuring transformer
S6 Control wire for alternate multi-purpose operation

The Receive Section

10.1.2
The incoming VF signal from the copper line or from a Siemens PLC equipment is fed in at the receive section.
The input is protected against overvoltages up to 2 kV that can be transferred to the transmission route by
coupling. The input impedance can be switched over from 600 Ω to approximately 5 kΩ.
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Figure 10-2
Protective circuit
Filter active
Isolating amplifier
Filter passive
Test socket
The desired signal is filtered out from any interference signals. The attenuation tolerance diagram of a band
pass filter is preset for the input filter. The pass band is from 500 Hz to 4000 Hz. The band-pass filter is imple-
mented by cascading an active low-pass and high-pass filter.
You can set the forward amplifier to 0 dB, +6 dB, and +12 dB with solder bridges. Greater immunity to 50-Hz
interference is obtained with the series-connected high-pass filter.
The signal is then transferred to the PU4. The receive signal can be measured at a test socket. The test socket
is decoupled via an isolating amplifier so that there is no interference of the desired signal through short-
circuits or insertion of signals. The same voltage level prevails at the test socket as at the input. The adjustable
thresholds for the level alarm relate to the input of the PU4 and not to the input of the CLE.

The Transmit Section

10.1.3
The desired signal supplied by the PU4 is amplified in the transmit section. There is no filtering as there is in
the receive section since the signal supplied does not have interference of this type. The PU4 supplies a level
up to +4 dB. The input signal is amplified by 11 dB to the range up to +15 dB.
The signal is extracted without voltage via a transformer with winding ratios that can be set to 1:2 or 1:16 and
matched to the output impedance. This impedance can be set to 600 Ω or 5 kΩ with links with the corre-
sponding output circuit.
Smart Communication, SWT 3000 Teleprotection, Equipment Manual
C53000-G6040-C605-1, Edition 03.2020
The Input Circuit of the CLE Module
Protective circuit
Filter active
Isolating amplifier
Filter passive
Test socket
Copper Line Equipment Module
10.1 Function Description
341