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12.2 Problem Solving
Fault / Problem
Detector does not power up
and does not follow the start-
up cycle
Detector powers up and goes
through start-up sequence,
then shows fault (LED
indicator goes amber)
Detector shows fault but power
and mA are correct
Detector shows warning
Detector is in inhibit state
4-20 mA output appears to be
unstable
PN 2331M1220 Issue 1
Description
Power supply is not available
Power supply is not within specification
Wiring connections are not made
correctly
External ambient temperature is below
-55°C or above +75°C
External ambient temperature is below
-30°C but above -55°C
Internal non-recoverable fault
Power supply is not within specification
mA loop is not wired correctly
mA loop external power supply and loop
impedance is not to specification
Power On Self Test failed
Diagnostic failure
Resistor is not fitted between mA- and
0 Vdc or between mA+ and +24 Vdc
terminals
Ambient operating temperature or power
is just over or just below specification
Detector has been inhibited by the
Searchzone Sonik mobile App or by HART
hand held device
Force command has been given by the
Searchzone Sonik mobile App or HART
hand held device
Electrical interference being
induced on 4-20 mA cabling
Poor contacts
Searchzone Sonik − Technical Manual
12 Problem Solving
Remedial Action
Check that power is available and to specification
Check that LED indicator in on
Check wiring connections
Check the ambient operating temperature. When Ex
certified equipment is operated outside its certified
range, its type approval certification is invalidated along
with its warranty. Such equipment should be removed
from service in potentially explosive atmospheres
When external temperature is below -30°C the detector
appears as not being powered during its warm-up
phase. LED status indicator is powered off, relays
de-energized and mA output is 0 mA. Internal heaters
are active and after a heat-up period the detector
initiates standard start-up cycle. Warm-up period
duration depends on external ambient temperature, to a
maximum of 30 minutes at -55°C. A good indication of
the heaters being active is the detector increased power
consumption of approximately 15 W
Return the detector to authorized service
Check that power is to specification
Check the mA loop wiring and rectify as necessary
Check that mA loop external power supply and loop
impedance is to specification
Interrogate event log to determine which diagnostic
failed
Re-power the detector and check if the fault clears
Otherwise return the detector to base
Power cycle the detector
Run diagnostics with the Searchzone Sonik mobile App
(menu Diagnostics - Logs)
Return the detector to authorized service
Add a suitable load resistor between mA- and 0 Vdc or
between mA+ and +24 Vdc terminals
Check location for heat sources
Fit with a sunshade or other protection
Change detector location
Release the output from inhibit state using the
Searchzone Sonik mobile App or HART hand held device
Check for earth loops
Confirm that the cable screen is earthed correctly
Investigate noise on the signal using an oscilloscope
For noisy installations, consider using filtering and
signal processing at the control card
Check terminal connections
If necessary tighten the connectors
Excessive vibration can loosen connections
Identify and minimise potential sources of
vibration
87
11/2018
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