Emerson Process Management OXYMITTER 4000 IM-106-340 - Manual (Page 117)

Instruction Manual
IM-106-340, Rev. 4.0
May 2006
Oxymitter 4000
http://www.processanalytic.com
Section 9 Maintenance and Service
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 9-1
Calibration with Keypad . . . . . . . . . . . . . . . . . . . . . . . . . . . page 9-1
Calibration with LOI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 9-5
Oxymitter 4000 Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 9-7
OVERVIEW This section identifies the calibration methods available and provides the
procedures to maintain and service the Oxymitter 4000.
CALIBRATION WITH
KEYPAD 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. A calibration record
sheet has been provided at the back of this section to track performance.
Before calibrating, verify that the calibration gas parameters are correct by
setting the gas concentrations used when calibrating the unit (see "Overview"
in Section 5: Startup and Operation of Oxymitter 4000 with Membrane
Keypad, or Section 6: Startup and Operation of Oxymitter 4000 with LOI) and
by setting the calibration gas flowmeter. The calibration gas flowmeter
regulates the calibration gas flow and must be set to 5 scfh. Only adjust the
flowmeter to 5 scfh after placing a new diffusion element 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
calibration gas is removed and the calibration gas line is blocked off. A
plugged diffusion element also can be indicated by a slightly lower reading on
the flowmeter.
Change the diffusion element when the calibration gas flowmeter reads
slightly lower during calibration or when response to the process flue gases
becomes very slow. Each time the diffusion element is changed, reset the
Install all protective equipment covers and safety ground leads after equipment repair or
service. Failure to install covers and ground leads could result in serious injury or death.