Emerson Process Management IM-106-340 Maintenance and Service, Overview Calibration with Keypad

Instruction Manual

IM-106-340, Rev. 4.0 May 2006

Oxymitter 4000

Section 9 Maintenance and Service

OVERVIEW

CALIBRATION WITH KEYPAD

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 9-1 Calibration with Keypad . . . . . . . . . . . . . . . . . . . . . . . . . . . page 9-1 Calibration with LOI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 9-5 Oxymitter 4000 Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 9-7

This section identifies the calibration methods available and provides the procedures to maintain and service the Oxymitter 4000.

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.

During a calibration, two calibration gases with known O2 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 O2 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 O2 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

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