Emerson Process Management OXYMITTER 4000 - Manual (Page 98)

Instruction Manual
IB-106-340C Rev. 4.1
July 2004
8-2 Troubleshooting Rosemount Analytical Inc. A Division of Emerson Process Management
Hazardous Area Oxymitter 4000
d. When flowing calibration gasses, the raw
cell millivolt value at test points 1 and 2
should represent the levels on the chart in
Figure 8-1. Note that the raw cell millivolt
value increases logarithmically as the O
2
concentration decreases.
Install all protective equipment covers
and safety ground leads after trouble-
shooting. Failure to install covers and
ground leads could result in serious
injury or death.
8-2 GENERAL
The troubleshooting section describes how to
identify and isolate faults that may develop in
the Hazardous Area Oxymitter 4000. When
troubleshooting, reference the following.
a. Grounding
It is essential that adequate grounding pre-
cautions are taken when installing the sys-
tem. Thoroughly check both the probe and
electronics to ensure the grounding quality
has not degraded during fault finding. The
system provides facilities for 100% effective
grounding and the total elimination of
ground loops.
b. Electrical Noise
The Hazardous Area Oxymitter 4000 has
been designed to operate in the type of
environment normally found in a boiler room
or control room. Noise suppression circuits
are employed on all field terminations and
main inputs. When fault finding, evaluate
the electrical noise being generated in the
immediate circuitry of a faulty system.
Ensure all cable shields are connected to
earth.
c. Loose Integrated Circuits
The Hazardous Area Oxymitter 4000 uses a
microprocessor and supporting integrated
circuits (IC). If the electronics are handled
roughly during installation or located where
subjected to severe vibration, the ICs could
work loose. Before troubleshooting the
system, ensure all ICs are fully seated.
d. Electrostatic Discharge
Electrostatic discharge can damage the ICs
used in the electronics. Before removing or
handling the processor board or the ICs,
ensure you are at ground potential.
8-3 ALARM INDICATIONS
The majority of the fault conditions for the
Hazardous Area Oxymitter 4000 will be indi-
cated by one of the four LEDs referred to as
diagnostic, or unit alarms on the operator’s key-
pad (Figure 8-2). An LED will flash a code that
will correspond to an error message. Only one
LED will blink at a time. An alarm code guide
is provided inside the screw-on cover for the
electronics.
Alarm indications will be also available via the
optional LOI or the HART Model 275/375 hand-
held communicator and Rosemount’s Asset
Management software. When the error is cor-
rected and/or power is cycled, the diagnostic
alarms will clear or the next error on the priority
list will appear.
DIAGNOSTIC
ALARMS
TEST
POINTS
HEATER T/C
HEATER
02 CELL
CALIBRATION
CALIBRATION RECOMMENDED
02 CELL mV +
02 CELL mv -
HEATER T/C +
HEATER T/C -
INC INC
DEC DEC
HIGH
GAS
LOW
GAS
CAL
TEST GAS +
PROCESS -
% 02
DIAGNOSTIC
LEDS
37260044
Figure 8-2. Diagnostic LEDs