Model NGA2000 PMD

Instruction Manual

760007-A July 2003

Range = 0% to 5% oxygen

Barometric pressure change after calibration = 1%

Analyzer Module measurement = 5% oxygen

Measurement error = 0.01 x 5% oxygen

Fullscale span = 5% oxygen

0.05% oxygen error = 1% of fullscale

The error is more significant for suppressed range 99% to 100%.

An optional barometric pressure compensation board is available to automatically perform this correction.

A general rule regarding calibration gas pressure is that it should be the same as the expected sample gas pressure during routine operation.

Flow Rate

Recommended sample flow rate is 800 to 1400 ml/min., ±40 ml/min. Optimum flow rate is 1100 ml/min.

If flow is held to within tolerance and operating pressure remains constant, zero and span drift will meet specified limits.

b.Connections

(See Figure 2-3 on page 2-4) Connect inlet and outlet lines for sample gas to appropriately labeled fittings on the rear panel. Both connections are 1/4 inch fer- rule-type compression fittings.

Zero and span gases use the same inlet and outlet as the sample. Figure 2-4 on page 2-5 shows a typical external sample handling manifold for gas selection. Par- ticulates must be filtered down to two mi- crons, gases generally require pressurization, and flow measurement metering MUST be present.

The above requirement increases the difficulty of operation at negative gauge pressure. A suction pump can be connected to the outlet port for drawing sample through the Analyzer Module. Such operation necessitates special precautions to ensure accurate readout, including the following:

The need for equilibrium between sample and gas calibration pressures.

Any leakage in the sample handling system will decrease readout accuracy.

c.Leak Test

The Analyzer Module is thoroughly tested at the factory for gas leakage. The user is responsible for testing for leakage only at the inlet and outlet fittings on the rear panel. The user is also responsible for in- ternal leak testing periodically and if any internal pneumatic components are ad- justed or replaced (with a test procedure selected by the user).

Rosemount Analytical Inc. A Division of Emerson Process Management

Installation 2-3