User guide

Percent Paramagnetic Oxygen Analyzer Operation 4
4-11
Teledyne Analytical Instruments
4.8.1.2 Manual Mode Spanning
ENTER SPAN from the MAIN MENU to start the SPAN function.
The screen that appears allows you to select whether the span calibration is
to be performed automatically or manually.
Span: Settling:MAN
<ENT> For Next
Use DOWN/UP to toggle between AUTO and MAN span settling. Stop
when MAN appears on the display. Use ENTER to move to the next screen.
Span Val: 20.90
<ENT>Span <UP>Mod #
Use UP to permit modification (Mod #) of span value.
Use ESCAPE/ENTER to choose the digit, and use DOWN/UP to
choose the value of the digit.
When you have finished typing in the concentration of the span gas you
are using, repeatedly select ENTER until the rightmost digit is reached, then, the
next ENTER will exit the Span Val field. One more ENTER will enter the new
span value, bring up the next screen, and start the span calibration.
Once the span has begun, the microprocessor samples the output at a
predetermined rate. It calculates the difference between successive samplings
and displays this difference as Slope on the screen. It takes several seconds
for the first Slope value to display. Slope indicates rate of change of the Span
reading. It is a sensitive indicator of stability.
#### % Span
Slope=#### ppm/s
When the Span value displayed on the screen is sufficiently stable,
ENTER it. (Generally, when the Span reading changes by 1 % or less of the
full scale of the range being calibrated for a period of ten minutes it is suffi-
ciently stable.) Once you ENTER it, the Span reading changes to the correct
value. The instrument then automatically enters the ANALYZE function.
4.9 Zero Cal
The ZERO function on the MAIN MENU is used to enter the zero
calibration function. Zero calibration can be performed in either the auto-
matic or manual mode. In the automatic mode, an internal algorithm com-
pares consecutive readings from the sensor to determine when the output is
within the acceptable range for zero. In the manual mode, the operator
determines when the reading is within the acceptable range for zero.
Make sure the zero gas is connected to the instrument.