Data Communication; Nsk600 Modem - ABB ETL600 Instruction Manual

ETL600
boost input, no boosting and disconnecting will take place. Boosting of
the built in NSD600 teleprotection devices have priority over boosting
of an external teleprotection equipment. Boosting of an external
teleprotection signal on APLC channel 1 has priority over boosting of
an external teleprotection signal on channel 2 which in turn has priority
over boosting of an external teleprotection signal on channel 3.
Note:
Note:
3.5.

Data Communication

ETL600 offers a variety of options for data communication: two
different types of modems for transmission over the PLC link and a
range of physical interfaces to be used with various transmission
formats.
3.5.1.

NSK600 Modem

The NSK600 is a new, fully programmable set of modems for data
transmission over power line carrier (PLC) links. For data transfer
rates of up to 1'200 bps it works with frequency shift keying (FSK) as
used in previous generation NSK modems; for 2'400, 4'800 and 9'600
bps it works with differential amplitude and phase shifted keying
(DAPSK).
NSK600 allows efficient low-cost link utilization, and since it comprises
four independent modems
module P4LT/P4LU, no additional hardware is required.
The NSK600 modems have been designed using digital signal
processor (DSP) and field programmable gate array (FPGA)
technology. This makes it very reliable and it requires no maintenance
or periodic adjusting.
NSK600 offers many features:
•
Full duplex 2-wire and 4-wire operation
3
If one of the modems is configured for 9'600 bps, only three NSK600
modems are supported.
Structure and Function
1KHW001489-EN
Certain rules - regarding alarm and signal weight
settings or configuration of the boost ratio - have to
be observed if commands of long duration or even
persistent commands are to be transferred with
external teleprotection over ETL600 (please refer to
Chapter 5 for details).
At beginning and end of NSD600 teleprotection
commands, external teleprotection equipment might
raise an SNR alarm. This is due to the large
transients produced by the boosted NSD600 trip
signal, when this signal is switched on or off.
3
that are included into the RF-Converter
November 2005
ABB Switzerland Ltd
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