Instruction Manual

245364-V May 2002

Model 755A

•Desired oxygen range for recorder output: 99% to 100%.

•Front panel TEST switch is set to position 4, and Recorder Oxygen Span Jumper is placed in 100% oxygen (1X gain) position.

•Required zero suppression is 99% oxygen, thus Recorder Zero Suppression Jumper is set in 80% position, and Recorder Zero Suppression Adj4ustments R41 and R104 are set for a reading of 99.00 volts on the digital display.

•Recorder Oxygen Span Jumper is returned to 1% oxygen (100X gain) position, normal span setting for 99% to 100% oxygen range. R88 may be used for fine span adjustment.

detector compartment with fingers; wait 30 seconds; re-apply power.

When on-scale reading is obtained, allow analyzer to warm up for at least one hour with gas flowing. This warm-up is necessary because a reliable calibration is obtainable only after the analyzer reaches temperature stability. Moreover, the resultant elevated temperature will ensure against condensation within, and possible damage to the detector assembly.

After analyzer warm-up, the digital display or recorder should give stable, drift-free readout; if so, proceed to Section 3.3. Otherwise refer to Section 6, Service and Maintenance.

3-4 CALIBRATION

Calibration for oxygen readout consists of establishing a downscale and upscale point.

•Set front panel TEST switch to position 1.

3-3 STARTUP PROCEDURE

WARNING

POSSIBLE EXPLOSION HAZARD

If gases are introduced into this analyzer, the sample containment system must be carefully leak-checked upon installation and before initial start-up, during routine maintenance and any time the integrity of the sample containment system is broken, to ensure the system is in leak-proof condition. Leak-check instructions are provided in Section 2-7, page 2-10.

Internal leakage of sample resulting from failure to observe these precautions could result in an explosion causing death, personal injury, or property damage.

Pass suitable on-scale gas (not actual sample) through the analyzer. Turn power ON. If digital display gives over-range indication, the probable cause is hang-up of the suspension within the detector assembly. To correct this condition, turn power OFF; tap

a.Calibration Using Digital Readout for Oxygen Readout

The digital display covers the full range of 0.00% to 100.005 oxygen and thus will normally be used as the readout device during calibration. If so, almost any down-scale and upscale standards may be used. Typically the downscale standard will be an oxygen-free gas such as nitrogen, and the upscale standard will be some readily obtained gas such as dry air (20.93% oxygen) or 100% oxygen. Purity requirements will be dictated by the accuracy requirements of the application.

b.Calibration Using Recorder for Oxygen Readout

In some applications the recorder readout may be the important display and may thus be used during calibration. If so, the down-scale standard gas is selected to establish a calibration point at or near the lower range-limit of the selected range:

1.A zero-based range normally uses an oxygen-free gas, typically nitrogen.

3-4 Operation

Rosemount Analytical Inc. A Division of Emerson Process Management