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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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Summary of Contents for REO 517
Page 10: ... RQWHQWV ...
Page 16: ...6 Introduction to the application manual KDSWHU QWURGXFWLRQ ...
Page 64: ...54 Blocking of signals during test KDSWHU RPPRQ IXQFWLRQV ...
Page 88: ...78 Scheme communication logic ZCOM KDSWHU LQH LPSHGDQFH ...
Page 146: ...136 Unbalance protection for capacitor banks TOCC KDSWHU XUUHQW ...
Page 166: ...156 Dead line detection DLD KDSWHU 3RZHU V VWHP VXSHUYLVLRQ ...
Page 378: ...368 Monitoring of DC analog measurements KDSWHU 0RQLWRULQJ ...
Page 384: ...374 Pulse counter logic PC KDSWHU 0HWHULQJ ...
Page 412: ...402 Serial communication modules SCM KDSWHU DWD FRPPXQLFDWLRQ ...
Page 440: ...430 LED indication module KDSWHU DUGZDUH PRGXOHV ...