Instruction Manual
IM-106-910Xi, Original Issue November 2010
Xi Advanced Electronics
Section 5 Troubleshooting
OVERVIEW OF OPERATING PRINCIPLES
Overview of Operating Principles . . . . . . . . . . . . . . . . . . . page 5-1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 5-2 Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 5-2 Electrical Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 5-3 Electrostatic Discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . page 5-3 Alarm Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 5-3 Identifying and Correcting Fault Indications . . . . . . . . . . page 5-3 Calibration Passes, but Still Reads Incorrectly . . . . . . . . page 5-4 Probe Passes Calibration, O2 Still Reads High . . . . . . . . page 5-5 Probe Passes Calibration, O2 Still Reads Low . . . . . . . . page 5-6 How do I detect a plugged diffuser? . . . . . . . . . . . . . . . . . page 5-6 Can I calibrate a badly plugged diffuser? . . . . . . . . . . . . page 5-6
When the Zirconium Oxide sensing cell is heated to its setpoint [736° C (1357° F)], the cell will generate a voltage that represents the difference between the process O2% and the reference O2% inside the probe (20.95% O2 instrument air).
When flowing calibration gases, the raw cell millivolt value should represent the levels on the chart in Figure 5-1. Note that the raw cell millivolt value increases logrithmically as the O2 concentration decreases.
