Emerson 8800 instruction manual Oxygen Concentration %

Instruction Manual

IM-106-880, Rev 1.0 January 2007

OCX 8800

Cal Warning (Calibration warning) Cal Failed (Calibration failed)

Probable Cause

Recommended Corrective Action

Calibration gas supply low or gas connection leaking

Check calibration gas supplies and connections. Adjust gas pressure and flow. Replenish low calibration gas supplies and tighten or repair loose or leaking connections. When calibration gas supplies are adequate, recalibrate.

O2 cell degraded or failed	Check O2 cell impedance by reading the O2 Snsr R value via HART (see Figure 4-3,
	sheet 2). If cell impedance is zero, replace O2 cell. If cell impedance is less than 5000
	ohms, check for cell housing ground fault. Repair ground fault. If cell impedance is
	greater than 5000 ohms and no ground fault is indicated, replace O2 cell.
	Flow calibration gas to the O2 cell. Read the cell millivolt output. Plot the cell millivolt
	output and the calibration gas O2 concentration on the chart shown in Figure 7-2.If the
	plotted values do not fall on the slope line shown in Figure 7-2,replace the O2 cell.
COe sensor degraded	Replace COe sensor or increase warning level (SYSTEM, CALIB SETUP, COe Slope
	Warn via HART.)
Low sample gas flow in sensor housing due to	Check the following portions of the flow path for plugging:
flow path plugging	•	blowback filter
	•	in-situ filter
	•	eductor outlet path

Table continued on next page

Figure 7-2. Oxygen and Cell

Output

OXYGEN CONCENTRATION (%)

20

(23)

10

9

8

7

6

5

4

3

2

(73)

1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

-20 0 20 40 60 80 100 120

ANALYZER OUTPUT (MILLIVOLT)

37390051

7-7