384
Short range galvanic module
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The short range galvanic modem is used for point to point synchronous data transmis-
sion at 64 kbit/s at distances up to 4 km. Transmission is performed simultaneously in
both directions, full duplex, over four wires in a communication (pilot wire) line ac-
cording to figure 207.
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Compared to normal data transmission standards, for example V.36, X.21 etc., the short
range modem increase the operational security and admits longer distances of transmis-
sion. This is achieved by a careful choice of transmission technology, modified M-3
balanced current loop and galvanic isolation between the transmission line and the in-
ternal logic of the protection terminal.
The reach will depend on the used cable. Higher capacitance between conductors and
higher resistance will reduce the reach. The use of screened cables will increase the ca-
pacitance and thereby shorten the reach but this will often be compensated by the re-
duced noise giving a better operational security. Maximum ranges as a function of cable
parameters are given in the diagram in figure 208.
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Содержание REO 517
Страница 10: ... RQWHQWV ...
Страница 16: ...6 Introduction to the application manual KDSWHU QWURGXFWLRQ ...
Страница 64: ...54 Blocking of signals during test KDSWHU RPPRQ IXQFWLRQV ...
Страница 88: ...78 Scheme communication logic ZCOM KDSWHU LQH LPSHGDQFH ...
Страница 100: ...90 Time delayed phase and residual overcurrent protection TOC1 KDSWHU XUUHQW Equation 36 Iset IsSEC I1b 100 ...
Страница 146: ...136 Unbalance protection for capacitor banks TOCC KDSWHU XUUHQW ...
Страница 166: ...156 Dead line detection DLD KDSWHU 3RZHU V VWHP VXSHUYLVLRQ ...
Страница 171: ...161 About this chapter KDSWHU RQWURO KDSWHU RQWURO ERXW WKLV FKDSWHU This chapter describes the control functions ...
Страница 293: ...283 About this chapter KDSWHU RJLF KDSWHU RJLF ERXW WKLV FKDSWHU This chapter describes the logic functions ...
Страница 378: ...368 Monitoring of DC analog measurements KDSWHU 0RQLWRULQJ ...
Страница 379: ...369 About this chapter KDSWHU 0HWHULQJ KDSWHU 0HWHULQJ ERXW WKLV FKDSWHU This chapter describes the metering functions ...
Страница 384: ...374 Pulse counter logic PC KDSWHU 0HWHULQJ ...
Страница 412: ...402 Serial communication modules SCM KDSWHU DWD FRPPXQLFDWLRQ ...
Страница 440: ...430 LED indication module KDSWHU DUGZDUH PRGXOHV ...