Teledyne 3020T Trace Oxygen Analyzer Operation SELF-TESTFunction, Zero and Span Functions

Trace Oxygen Analyzer Operation 4

4.7The SELF-TESTFunction

The Model 3020T has a built-in self-testing diagnostic routine. Prepro- grammed signals are sent through the power supply, output board and sensor circuit. The return signal is analyzed, and at the end of the test the status of each function is displayed on the screen, either as OK or as a number between 1 and 3. (See System Self Diagnostic Test in chapter 5 for number code.)

The self diagnostics are run automatically by the analyzer whenever the instrument is turned on, but the test can also be run by the operator at will. To initiate SELF-TESTduring operation:

Use the DOWN/UP control to scroll through the MAIN MENU to SELF- TEST. The screen will follow the running of the diagnostic.

RUNNING DIAGNOSTIC

Testing Preamp — 83

During preamp testing there is a countdown in the lower right corner of the screen. When the testing is complete, the results are displayed.

Power: OK	Analog: OK
Preamp: 3

The module is functioning properly if it is followed by OK. A number indicates a problem in a specific area of the instrument. Refer to Chapter 5 Maintenance for number-code information. The results screen alternates for a time with:

Press Any Key

To Continue...

Then the analyzer returns to the ANALYZE screen.

4.8The ZERO and SPAN Functions

Zeroing is not required in order to achieve the published accuracy specification of this unit.

Zeroing will eliminate offset error contributed by sensor, elec- tronics, and internal and external sampling system and im- prove performance beyond published specification limits.

The analyzer is calibrated using zero and span gases.

Any suitable oxygen-free gas can be used for zero gas as long as it is known to be oxygen free and does not react adversely with the sample system.

Teledyne Analytical Instruments 4-9