Teledyne 3020T - Manual (Page 48)

4 Operation Model 3020T
4-12 Teledyne Analytical Instruments
4.8.1.3 Cell Failure
Cell failure in the 3020T is usually associated with inability to zero the
instrument down to a satisfactorily low ppm reading. When this occurs, the
3020T system alarm trips, and the VFD displays a failure message.
#.# ppm Anlz
CELL FAIL/ ZERO HIGH
Before replacing the cell:
a. Check for leaks downstream from the cell, where oxygen may be
leaking into the system.
b. Check your span gas to make sure it is within specifications.
c. If there are no leaks and the span gas is OK, replace the cell as
described in chapter 5, Maintenance.
d. After correcting the condition, reset the Cell Fail Alarm by taking
the analyzer into, and then back out of, STANDBY.
4.8.2 Span Cal
SPAN is used to span calibrate the analyzer. Span calibration can be
performed using the automatic mode, where an internal algorithm compares
consecutive readings from the sensor to determine when the output matches
the span gas concentration. Span calibration can also be performed in
manual mode, where the operator determines when the span concentration
reading is acceptable and manually exits the function.
4.8.2.1 Auto Mode Spanning
Scroll to SPAN , and ENTER the SPAN function. The screen that
appears allows you to select whether the span calibration is to be performed
automatically or manually. Use the DOWN/UP
control to toggle between
AUTO and MAN span settling. Stop when AUTO appears on the display.
Span: Settling: AUTO
For Next
Use ENTER to move to the next screen.
Span Val: 209000.00
Span Mod #
Use DOWN/UP to start changing the oxygen-concentration. Use
ESCAPE/ENTER to blink the digit you are going to modify. Use DOWN/UP
again to change the value of the selected digit. When you have finished