User's Manual

Photometric Analyzer Operation /Control Unit 3
Part I 3-17
Teledyne Analytical Instruments
zero calibration is to be performed automatically or manually. Use the DÑ
arrow keys to toggle between AUTO and MAN zero settling. Stop when
AUTO appears, blinking, on the display.
Select zero
mode: AUTO
Press Enter to begin zeroing.
####.## % SO2
Slope=#.### C—Zero
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= in percent/second (unless the Slope starts within the acceptable
zero range and does not need to settle further). The system first does a coarse
zero, shown in the lower right corner of the screen as C—Zero , for 3 min, and
then does a fine zero, and displays F—Zero , for 3 min.
Then, and whenever Slope is less than 0.01 for at least 3 min, instead of
Slope you will see a countdown: 9 Left, 8 Left, and so fourth. These are
software steps in the zeroing process that the system must complete, AFTER
settling, before it can go back to Analyze. Software zero is indicated by S–
Zero in the lower right corner.
####.## % SO2
4 Left=#.### S—Zero
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 mode.
3.4.1.2 Manual Mode Zeroing
Press Zero to enter the Zero function. The screen that appears allows
you to select between automatic or manual zero calibration. Use the DÑ
keys to toggle between AUTO and MAN zero settling. Stop when MANU-
AL appears, blinking, on the display.
Select zero
mode: MANUAL
Press Enter to begin the zero calibration. After a few seconds the first
of three zeroing screens appears. The number in the upper left hand corner is
the first-stage zero offset. The microprocessor samples the output at a prede-
termined rate.