Teledyne 9110T - Nitrogen Oxides Analyzer - Manual (Page 202)

Model 9110T NOx Analyzer Calibration Procedures
Teledyne Analytical Instruments 202
9.3. MANUAL CALIBRATION WITH THE INTERNAL SPAN GAS
GENERATOR
I
MPORTANT I MPACT ON R EADINGS OR D ATA
The internal span gas generator’s NO2 permeation tube has a limited
accuracy of about ±5%. In the USA this may be sufficient for informal
calibration checks (Section 9.3.4), but it is NOT approved by the US EPA
as a calibration source.
9.3.1. PERFORMING “PRECISION” MANUAL CALIBRATION WHEN
INTERNAL SPAN GAS (IZS) GENERATOR OPTION IS PRESENT
It is necessary to perform a precision calibration using more accurate zero and span gas standards prior
to IZS span calibration or cal check.
To perform a precision calibration of the 9110T, connect external sources of zero air and calibrated span
gas (Section 9.1.2) and temporarily disconnect the sample gas source as shown below; then follow the
procedures described in Section 9.2.3.
Figure 9-3: Pneumatic Connections for 9110T Precision Calibration when IZS Generator Present
I MPORTANT
I MPACT ON R EADINGS OR D ATA
DO NOT USE THE CALZ or CALS buttons even though they will be visible,
as this will cause the instrument to use the internal zero air and span gas.
Instead, press the CAL button. This will cause the analyzer to use the
external calibration gas sources.