Emerson Rosemount OCX 8800, Instruction Manual

Page: 123 / 306

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