Honeywell UDA2182 manual 15.16Appendix O Auto Clean and Auto Cal Examples

Appendices

15.16Appendix O – Auto Clean and Auto Cal Examples

Automatic Cleaning and Calibration

Overview

Although the Honeywell probe accuracy is unaffected by inert fouling, there are two conditions where probe cleaning may be required. (These conditions affect all conventional dissolved oxygen probes as well.)

The first is where the fouling is so thick that the response time of the probe becomes unacceptably long. The second is where organic fouling is consuming oxygen before it reaches the surface of the probe.

A feature allowing automatic cleaning at preconfigured times is included in the UDA2182 analyzer. Cleaning may be initiated with a frequency of every few minutes to monthly.

Cleaning

Functionally, relays within the analyzer are tripped, allowing withdrawal of the probe from the sample, turning on a cleaning spray, turning off the spray, and reinserting the probe into the sample. Execution of automatic cleaning and calibration requires you to install a drive unit, a solenoid valve, and mounting hardware. See Figure 15-9

Calibration

Similarly, all probes drift with time. Although the Honeywell probe is very stable, included in the analyzer is a feature that allows withdrawal of the probe into air for automatic air calibration at user-configured times.

The sequence of calibrations and cleanings are user-configurable.

Low Dissolved Oxygen

One symptom of the need for cleaning is a low dissolved oxygen reading. The UDA2182 dissolved oxygen analyzer can be configured to execute a cleaning cycle if the measured dissolved oxygen falls below a user-selected value. An alarm can be configured to alert you if the cleaning fails to restore the dissolved oxygen to a higher level. The alarm will indicate either a true decrease in dissolved oxygen concentration or unsuccessful cleaning.

January 2009 UDA2182 Universal Dual Analyzer Product Manual 231