Trip Frequencies - ABB ETL600 Instruction Manual

ETL600
command. Transmitting two discrete frequencies gives added security
against speech and interference, e.g. an audio frequency generator.
Compared to single tone command signals, the multiplex dual tone
command signal has the same amplitude (peak envelope power), but
3 dB lower rms power since each tone is transmitted at a 6 dB lower
voltage level.
Amplitude
In order to reduce the transmission time, the NSD600 tripping signals
are not relayed through the equalizer. The NSD600 receiver is
therefore designed that it is able to handle a wide range of magnitude
distortion within the speech band.
3.6.8.4.2.

Trip frequencies

The following seven preset frequencies given below are provided in
the PLC speech frequency band (0.3 ... 2.0 kHz).
Trip signal frequencies
With seven frequencies 21 dual tone tripping signals can be achieved.
16 of them are used by the NSD600 to transmit its four independent
commands and their combinations plus a test signal.
The nominal tripping signal level with minimal boosting (0...6 dB) has
the same value as the test signal level, it is 0 dBm0 or equal to the
guard level (whatever is higher).
Structure and Function
1KHW001489-EN
Speech Band
F1 F2 F3 F4 F5 F6 F7 G
Fig. 3-42 Dual-tone principle
F1 = 356 Hz
F2 = 598 Hz
F3 = 841 Hz
F4 = 1083 Hz
F5 = 1325 Hz
F6 = 1568 Hz
F7 = 1810 Hz
ABB Switzerland Ltd
Frequency
Guard signal
Trip
signal
Frequency
November 2005
Time
3-75