4003_5001_D02
Page 9 of 35
4.4.
DETECTION MODE
There are two DETECTION METHODS. The default PIG PASS mode detects when the PIG has
likely to have PASSED the signaller and DETECTION ONLY detects the presence of a pig but not
necessarily that it has passed. The latter is useful when trying to determine when a PIG has
been launched, wh
ere the pig is initially present, and the pig’s movement will be away from the
signaller
–
i.e. will not create a flux peak.
4.4.1.
PIG PASSED
Once the gauss reading crosses the threshold,
DETECTION starts, the pig state changes to PIG
APPROACH and the pig approach screen is shown. The
GAUSS reading shows the live gauss reading.
PIG PASSED is signalled when the flux reading has
peaked and fallen by a defined drop as specified by
the DETECTION CRITERIA, reference section 4.5.11
DETECTION METHOD. The larger the defined drop,
the more likely that the pig has passed the unit.
However, if the signaller is located close to the pig
receiver, then a smaller drop should be considered as
the pig’s magnetic signal may not fully clear the
signaller.
During DETECTION the display shows PIG nnn
PASSED and the LEDs around the display will flash
every 1 second and the relay and current loop outputs
will be in the DETECTION state, the unit will keep
logging until its internal buffer is full (or the CONTROL
BUTTON is firmly pressed), the event will then be
logged.
If DETECTION starts and the pig does not pass the
signaller, the signaller will timeout after 3 minutes
and 20 seconds the signaller and will return to
LISTENING (no DETECTION delay), the data will be
logged but no event will be signalled. In this situation,
the pig has been detected but is likely to have stopped
before the signaller. If the pig then moves and passes
the signaller (providing the gauss value exceed the
THRESHOLD was far enough away to cause a peak
–
otherwise the signaller will timeout again and log the
data), a PIG PASSED event is likely to be triggered If
the unit is in LP MODE, the screen will stay on until
DETECTION completes or the unit times out and
reverts to LISTENING where normal LP mode will
resume.
4.4.2.
PIG DETECTION ONLY
Once the gauss reading crosses the threshold, DETECTION starts, the pig state changes to PIG
APPROACH and the pig approach screen is shown. The gauss reading shows the live gauss
reading.
THRESHOLD
EXCEEDED
PIG DETECTION
DETECTED ONLY
PRESS/
TIMEOUT
LISTENING
DISPLAY OFF
LISTENING
13 EVENTS
LISTENING
DISPLAY OFF
(LP MODE)
10 SEC
TIMEOUT
EVENT
TRIGGERED
OR
PIG APPROACH
PIG DETECTION
PASSED
Summary of Contents for 4003 MAGSIG
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