Emerson Rosemount OCX 8800 - Transducer block

Descriptions of PlantWeb Alerts (continued)Table 7-3:
Alerts Alarms AMS tab
What does the
alert indicate?
Recommended
action Description
also cause this
alarm. Refer
to Section 8.2
for details.
Sensor Degraded Transducer block:
O
2
Cell Impe-
dance High
Sensor Alerts This alert is active
when the oxygen
sensor impedance
indicates that the
cell is beyond its
useful life.
Replace the oxy-
gen cell.
Oxygen cells de-
grade over time
due to aging and
corrosion. An in-
creasing cell re-
sistance is a good
indicator of re-
duced cell per-
formance. As the
cell impedance in-
creases, the cell
output falls off,
and response
time increases.
Calibrating the in-
strument com-
pensates for the
increased cell re-
sistance up to sev-
eral hundred
ohms, beyond
which the cell is
no longer func-
tional. Diagnosis
must be done at
the analyzer. Re-
fer to Section 8.2
for details.
Foundation Fieldbus
Reference Manual 103