Teledyne 3020T User Manual

Page 47

Trace Oxygen Analyzer

Operation 4

4-11

Teledyne Analytical Instruments

The beginning zero level is shown in the upper left corner of the dis-

play. As the zero reading settles, the screen displays and updates information
on

Slope (unless the Slope starts within the acceptable zero range and does

not need to settle further).

Then, and whenever Slope is less than 0.08 for at least 3 minutes,

instead of Slope you will see a countdown:

1 Left, 0 Left, and so fourth.

These are two steps in the zeroing process that the system must complete,
AFTER settling, before it can go back to ANALYZE.

#### PPM Zero

1 Left=### ppm/s

The zeroing process will automatically conclude when the output is

within the acceptable range for a good zero. Then the analyzer automatically
returns to the ANALYZE screen.

4.8.1.2

Manual Mode Zeroing

ENTER the

ZERO

function. The screen that appears allows you to

select between automatic or manual zero calibration. Use DOWN/UP to
toggle between

AUTO and MAN zero settling. Stop when MAN appears on

the display.

Zero: Settling: Man

To Begin

ENTER to begin the zero calibration. After a few seconds the first of

five zeroing screens appears. The number in the upper left hand corner is the
first-stage zero offset. The microprocessor samples the output at a predeter-
mined rate. It calculates the differences between successive samplings and
displays the rate of change as

Slope= a value in parts per million per second

(ppm/s).

#### ppm Zero

Slope=#### ppm/s

NOTE:It takes several seconds for the true

Slope

value to display.

Wait about 10 seconds. Then, wait until

Slope

is sufficiently

close to zero before using

ENTER

to finish zeroing.

Generally, you have a good zero when

Slope is less than 0.05 ppm/s

for about 30 seconds. When

Slope is close enough to zero, ENTER it. In a

few seconds, the screen will update.

Once zero settling completes, the information is stored in the

microprocessor, and the instrument automatically returns to the ANALYZE
screen.

This manual is related to the following products:

3020T - Explosion proof trace oxygen analyzer