Emerson Rosemount OCX8800 Instruction Manual page 123

Instruction Manual
IM-106-880C, OI
Alerts Alarms
Sensor Heater Transducer
Malfunction Block
1) O Heater
2
Failure
2) Comb
Heater Failure
3) SB Heater
Failure
4) O Heater
2
Ramp Rate
Exceeded
5) Comb
Heater Ramp
Rate Exceeded
6) SB Heater
Ramp Rate
Exceeded
7) Heater Relay
Failed
Sensor Heater Transducer
Over Temp- Block:
erature 1) O Cell
2
Temp. Very
High
2) CombTemp.
Very High
3) SB Temp
Very High
Transducer
Sensor Heater
Block:
Temp-
1) O Cell
erature
2
Temp. Low
Variance
2) O Cell
2
Temp. High
3) CombTemp.
Low
4) CombTemp.
High
5) SB Temp.
Low
6) SB Temp.
High
Transducer
Calibration
Block:
Error
1) O
2
Calibration
Failed
2) Comb
Calibration
Failed
3) Calibration
Warning
Mapping of PWA
What does
the alert
AMS
Tab indicate?
T/C This alert
Heater indicates that
Alerts no measurable
heat energy is
being detected check
at the oxygen
sensor or that
the heater
temperature is
rising too fast.
TC This alert
Heater indicates a very
Alerts high heater
temperature;
temperature is
rising too fast.
T/C This alert
Heater indicates a
Alerts sensor heater
temperature
that is too high
or too low.
Calib- This alert
ration indicates that
Alerts the slope and
constant
values
determined
from the
calibration did
not fall within
an acceptable
range.
Recommended
Action Description
Check heater Mechanical or thermal stress may eventually
circuit for lose or cause the sensor heater to fail. The resistance
broken of a properly functioning cell heater will
connections, measure less than 100 ohms. A failed heater
will generally measure as an open circuit.
thermocouple Diagnosis must be done at the analyzer. Refer
wiring, test or to Section 8, Overview page 165 for details.
replace the
heater. The Heater Ramp Rate Exceeded problem is
usually caused by the inability of the device
to limit power to the heater. This could be
caused by a shorted triac component on the
power supply in the electronics stack.
Diagnosis must be done at the analyzer. Refer
to Section 8, Overview page 165 for details.
Check heater A heater over-temperature/out of control
wiring, check problem would generally be caused by the
thermocouple inability of the device to limit power to the
wiring or replace heater. This could be caused by a shorted
the electronics triac on the power supply in the electronics
stack. stack.
Allow instrument Cell temperature control may become erratic
several minutes to for the following reasons:
reach proper 1) Temperature is settling during startup.
temperature or 2) Large variations in process temperature or
check power flow.
supply. 3) Fluctuations or noise in the power supplied
to the instrument.
Check the Make sure the oxygen concentrations of the
calibration gas calibration gases match the concentration
supplies and values in the device. If the calibration has
connections. been performed correctly this alarm may
indicate that the sensor requires
replacement. Refer to Section 8, Overview
page 165 for details.
Section 7: Foundation
Fieldbus
April 2017
97