Zeroing - Emerson NGA2000 Reference Manual

NGA2000 Reference
1-6

ZEROING

Zeroing is the function of adjusting the ana-
lyzer's offset so that when given a zero gas, it
reads zero, no matter how the analyzer span is
set. By extension this includes adjusting the low
end of a suppressed range, although in this
case the span setting will have an effect on the
low end reading.
a. Basic instructions
No Autocal Module
Select the analyzer you want to zero.
Flow zero gas through the analyzer.
Press "MENUS" or "HOME" to enter the
Main menu.
Select Basic controls...
When it is stable, press "ZERO".
Press "ZERO again on the "Are you sure?"
screen.
Press "HOME" to get back to the Main
menu.
Autocal module
Select the analyzer you want to zero.
Press "MENUS" or "HOME" to enter the
Main menu.
Select Expert controls and setup
Select Auxiliary module controls...
Select the Autocal module, whatever you
have called it.
Either do a complete auto-calibration from
the first screen that appears (by pressing
"START"), or
Select Manual calibration function...
Set the Gas to be used for calibration: to
"Zero gas".
Rosemount Analytical Inc. A Division of Emerson Process Management
Select the correct range to zero with Meas-
urement range number:
Select CAL in the Calibration or QC check:
line.
Press "START".
You can press "ABORT" to abort the cali-
bration, and then press it again to cut short
the sample purge time if you want.
b. Advanced Instructions
No Autocal module
Select the analyzer you want to zero.
Flow zero gas through the analyzer.
Enter the Main menu.
Select Expert controls and setup
Select Expert analyzer controls...
Select the range you want to zero.
Verify gas flow.
Press CAL or select Zero/span calibration...
Press "ZERO".
Press "ZERO" again.
Press the left arrow.
Select Result...
Examine the Calibration results screen to
see how well you did.
If desired, press the left arrow key to return
to the calibration screen.
Press "FACTORS".
Select the calibration factors for the range
you are on.
View the factors, and if desired, edit the
"Zero factor" to the raw signal number
Reference Manual
748384-C
September 2003
Introduction 1-13