Emerson Process Management OXYMITTER 4000 - Manual (Page 31)

Instruction Manual
IB-106-340C Rev. 4.1
July 2004
Rosemount Analytical Inc. A Division of Emerson Process Management Description and Specifications 1-1
Hazardous Area Oxymitter 4000
SECTION 1
DESCRIPTION AND SPECIFICATIONS
1-1 COMPONENT CHECKLIST OF TYPICAL
SYSTEM (PACKAGE CONTENTS)
A typical Rosemount Hazardous Area Oxymitter
4000 Oxygen Transmitter should contain the
items shown in Figure 1-1. Record the part
number, serial number, and order number for
each component of your system in the table
located on the first page of this manual.
The Oxymitter 4000 is offered in both
hazardous area and general purpose
configurations. The hazardous area
version has special markings on the
approval label. The general purpose
version does not. If you received the
general purpose version, ensure you
do not install it in a potentially explo-
sive atmosphere.
Also, use the product matrix in Table 1-1 at the
end of this section to compare your order num-
ber against your unit. The first part of the matrix
defines the model. The last part defines the
various options and features of the Hazardous
Area Oxymitter 4000. Ensure the features and
options specified by your order number are on
or included with the unit.
1-2 SYSTEM OVERVIEW
a. Scope
This Instruction Bulletin provides the infor-
mation needed to install, start up, operate,
and maintain the Hazardous Area Oxymitter
4000. Signal conditioning electronics out-
puts a 4-20 mA signal representing an O
2
value and provides a membrane keypad or
full function Local Operator Interface (LOI)
for setup, calibration, and diagnostics. This
same information, plus additional details,
can be accessed with the
HART Model 275/375 handheld communi-
cator or Asset Management Solutions
(AMS) software.
b. System Description
The Hazardous Area Oxymitter 4000 is
designed to measure the net concentration
of oxygen in an industrial process; i.e., the
oxygen remaining after all fuels have been
oxidized. The probe is permanently posi-
tioned within an exhaust duct or stack and
performs its task without the use of a
sampling system.
The equipment measures oxygen percent-
age by reading the voltage developed
across a heated electrochemical cell, which
consists of a small yttria-stabilized, zirconia
disc. Both sides of the disc are coated with
porous metal electrodes. When operated at
the proper temperature, the millivolt output
voltage of the cell is given by the following
Nernst equation:
EMF = KT log10(P1/P2) + C
Where:
1. P2 is the partial pressure of the oxy-
gen in the measured gas on one side
of the cell.
2. P1 is the partial pressure of the oxy-
gen in the reference air on the oppo-
site side of the cell.
3. T is the absolute temperature.
4. C is the cell constant.
5. K is an arithmetic constant.
NOTE
For best results, use clean, dry, instru-
ment air (20.95% oxygen) as the refer-
ence air.
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