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Teledyne API Model T201 NH
3
Analyzer Operator Manual Calibration Procedure
07271B DCN6646 17
Table 2-2. Zero Calibration Procedure - Zero Gas through ZERO Port
Step No.
Action Comment
1. Press CALZ The T201 enters the calibrate mode from sample
mode. The zero gas is supplied through the ZERO
inlet port on the rear panel of the M501 NH
3
.
2 Table 2.1 Follow Steps 2 to 8 in Table 2-1.
Notes
Since the zero gas concentration is defined as 0 ppb, it is not necessary
to enter the expected concentration values.
Both the TN
x
and NO
x
channels must be zeroed individually. When you
zero the NO
x
channel both the offsets for NO
x
and NO are configured.
All readings should display zero following this action.
It is recommended that the calibration of both the TN
x
and NO
x
channels
be done at one time.
Always confirm that excess zero air is flowing past the sample or zero
port, if the Zero/Span option is present, on the rear of the M501 NH
3
converter. There should always be some excess flow. If insufficient flow
is supplied to the analyzer ambient gas will be entrained and the zero
offset values will be incorrect. However, it is important not to over
pressurize the analyzer.
It is a good idea to allow the analyzer to sample zero gas for extended
periods following zero calibration. Large drifts can signify leaks or
indicate an issue with the zero air source.
2.2 SPANNING THE ANALYZER WITH NITRIC OXIDE GAS
The analyzer can be spanned by either applying nitric oxide gas straight to
the Sample port or through the Zero/Span valve option, if installed. It is
important to remember that if the analyzer was previously sampling
ammonia gas, prior to conducting a nitric oxide span calibration, it will
take some period of time before the TN
x
channel stabilizes. The process of
spanning the analyzer consists of diluting bottled gas, using a calibrator
and delivering to the analyzer. The operator then manually spans the TN
x
and NO
x
channels individually through the user interface. The following
Tables outline the manual steps necessary to span the analyzer.