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RANSMITTER
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4.3 Options for direct and inductive signal coupling
There are four methods of coupling the signal from the transmitter to the line:
•
Direct coupling to cables and pipes (see below)
•
Coupling using special connection accessories (see page 13)
•
Inductive signal coupling (see page 14)
•
Signal coupling in non-metallic pipes (see page 15)
4.3.1 Direct coupling to cables and pipes
Direct galvanic coupling is practical
for cables which are easily accessible
and free of current.
The
method
of
dependent upon the position and
nature of the lines (e.g. insulation,
cable conduit, accessibility of the
cable ends) - see the following pages
for examples of direct coupling
methods.
Direct coupling presents a reliable
option for selective cable location, as
the signal can be coupled to a specific
cable with virtually no loss.
If the lines being located are energised, the following five safety precautions must be
taken before connecting the transmitter:
Five safety precautions:
1. Disconnect power
2. Secure against reconnection.
3. Check to ensure no voltage present.
4. Make each connection and short circuit the line.
5. Cover or block access to adjacent components which are energised.
a.
If disconnection is not possible, use the transmitter clamp method - see
"Coupling via transmitter clamp" on page 13.
10
R
SETUP AND SIGNAL COUPLING
connection
is
a
from the line.
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