
Leaders in Pipelin
e Survey Systems
C
C
C
-
-
-
S
S
S
C
C
C
A
A
A
N
N
N
2
2
2
0
0
0
1
1
1
0
0
0
SYSTEM MANUAL Version 6.03i
22
Fig 4.3 – Fixing earth spikes perpendicular to pipeline
Use of existing ground points (other than TR/CP ground beds), such as water pipes, lamp
posts, steel fences, pylons, etc., may be necessary in some situations but must be chosen
with care. If such structures are used as ground points it is essential to ensure that they
do not approach or cross over the pipeline being surveyed at any point. When using a
pylon, or similar, as an earth it must be noted that any system to ground failure of the
mains electric being carried could damage the Signal Generator. Similarly the likelihood of
any metal structure being struck by lighting has to be assessed
4.5. Setting the Signal Current
Only when Pipe and Earth connections have safely been made, should the Signal
Generator should be switched ON. The Signal Generator will carry out its own internal
checks. When these checks are completed satisfactorily, the Operator can set the signal
current. The flow diagrams in sections 4.9 and 4.10 below, outlines this process.
The signal current is set using the
AUTO
,
MANUAL
or
RECALL
keys:
AUTO:
Pressing the
AUTO
key automatically sets the current to 600 mA. If the
resistance of the ground/pipe circuit is such that 600mA cannot be attained
then the Signal Generator will automatically set the current as close to 600mA
as possible. If the signal is satisfactory, the survey can start.
MANUAL: To manually set a current, hold the
AUTO
key to enter MANUAL mode and
choose the current using the
▲▼
keys. When the chosen current is displayed
press the
AUTO
key again to set the generator to this current.
RECALL: Pressing the
RECALL
key will set the generator to the value that has been
previously stored.