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Instruction Manual
IB-106-340 Rev. 2.4
April, 2001
Rosemount Analytical Inc. A Division of Emerson Process Management Maintenance and Service 6-1
Oxymitter 4000
SECTION 6
MAINTENANCE AND SERVICE
6-1 OVERVIEW
This section identifies the calibration methods
available and provides the procedures to main-
tain and service the Oxymitter 4000 and optional
integrally mounted SPS 4000.
Install all protective equipment covers
and safety ground leads after equip-
ment repair or service. Failure to in-
stall covers and ground leads could
result in serious injury or death.
6-2 CALIBRATION
a. During a calibration, two calibration gases
with known O
2
concentrations are applied to
the Oxymitter 4000. Slope and constant
values calculated from the two calibration
gases determine if the Oxymitter 4000 is
correctly measuring the net concentration of
O
2
in the industrial process.
Before calibrating the Oxymitter 4000, verify
that the calibration gas parameters are cor-
rect by setting the gas concentrations used
when calibrating the unit (See paragraph
4-1a.5) and by setting the calibration gas
flowmeter.
The calibration gas flowmeter regulates the
calibration gas flow and must be set to
5 scfh. However, only adjust the flowmeter
to 5 scfh after placing a new diffusion ele-
ment on the end of the Oxymitter 4000.
Adjusting the flowmeter at any other time
can pressurize the cell and bias the
calibration.
In applications with a heavy dust loading,
the O
2
probe diffusion element may become
plugged over time, causing a slower speed
of response. The best way to detect a
plugged diffusion element is to note the time
it takes the Oxymitter 4000 to return to the
normal process reading after the last cali-
bration gas is removed and the calibration
gas line is blocked off. A plugged element
also can be indicated by a slightly lower
reading on the flowmeter.
Change the diffusion element when the cali-
bration gas flowmeter reads slightly lower
during calibration or when the response time
to the process flue gases becomes very
slow. Each time the diffusion element is
changed, reset the calibration gas flowmeter
to 5 scfh and calibrate the Oxymitter 4000.
To change the diffusion element, refer to
paragraph 6-8.
b. Three types of calibration methods are
available: automatic, semi-automatic, and
manual.
NOTE
A calibration can be aborted any time
during the process by pressing the
CAL key (Figure 6-2) on the Oxymitter
4000 keypad three times in a three
second interval or via HART/AMS or
an IMPS 4000. An aborted calibration
will retain the values of the previous
good calibration.
1. Automatic Calibration. Automatic cali-
brations require no operator action.
However, the calibration gases must
be permanently piped to the Oxymitter
4000, an SPS 4000 or IMPS 4000
must be installed to sequence the
gases, and the Oxymitter 4000’s logic
I/O must be set to mode 8 via HART/
AMS so the sequencer and Oxymitter
4000 can communicate.
Depending on your system setup, an
automatic calibration can be initiated
by the following methods:
(a) The Oxymitter 4000’s CALIBRA-
TION RECOMMENDED alarm sig-
nals that a calibration is required.
(b) Enter a “time since last cal” pa-
rameter (CAL INTRVL) via HART/
AMS that will initiate an automatic
calibration at a scheduled time in-
terval (in hours). To configure the
CAL INTRVL parameter, refer to
paragraph 5-8.
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