Teledyne 9110AH - Nitrogen oxides analyzer - Manual (Page 62)

TELEDYNE Model 9110AH NO
X
Analyzer Operator Manual, 01620, Rev. F
5-20
4. CALIBRATION
When the above selections have been made, the instrument now must be calibrated through the
dilution probe.
NOTE
Units are now in PPM. See Section 7.1 for calibration methods.
5.3.4.5 Concentration Units
The M9110AH can display concentrations in ppm and mg/m
3
. To change the current units press
SETUP-RANGE-UNIT. Select PPM or MGM, then press ENTR. Remember, you should now
reset the expected span concentration values in the new units and re-calibrate the instrument
using one of the methods in Section 7. The following equations give approximate conversion
values. The exact values depend on the standard temperature and pressure used by your
regulatory agency.
NO ppm x 1.34 = NO mg/m 3
NO
2
ppm x 2.05 = NO
2
mg/m
3
NOTE
Changing units affects all of the RS-232 values, all of the
display values, and all of the calibration values.
Example:
If the current units are in ppm with the span value at 400 ppm, and
the units are changed to mg/m 3 the span value is NOT re-calculated
to the equivalent value in mg/m
3
. Therefore the span value now
becomes 400 mg/m 3 instead of 400 ppm. Re-enter the expected
span concentrations in mg/m3 units and recalibrate.
5.3.4.6 Recorder Offset
If necessary, a recorder offset can be introduced into the analog output voltages. This can be
used to bias the output voltage or current 10%. It is intended for older design chart recorders
that cannot show slightly negative readings. It can also be used to bias the input to a datalogger
to offset small external ground loop voltages that are sometimes present in monitoring systems.
To set the recorder offset, press SETUP-RANGE-OFFS and enter the offset voltage desired in
percent. The recorder offset will bias both the recorder and DAS analog outputs.