Teledyne API Model 200AH NOX Analyzer Instruction Manual, 06492, Rev. G2
7-12
Table 7-10: Calibration Requirements for AutoRange or Remote Range
No matter which calibration method you choose from this chapter, all of the following
parameters must be set to properly calibrate the instrument on AutoRange or Remote range.
Parameter Low Range High Range
Range Low Range is selected by pressing
CONC-LO on the front panel. High Range is selected by pressing
CONC-HI on the front panel.
Slope NOX and NO slopes for low range
are set by span calibration. NOX and NO slopes for high range
are set by span calibration.
Offset NOX and NO offsets for low range
are set by zero calibration. NOX and NO offsets for high range
are set by zero calibration.
Converter Efficiency CE can be set by one of the
procedures in Section 7.11.
Converter efficiency is optional.
CE can be set by one of the
procedures in Section 7.11.
Converter efficiency is optional.
In Independent Range mode there is one set of calibration parameters. That is, NOX and NO
slopes and NOX and NO offsets, and one converter efficiency parameter. The calibration of the
M200AH using independent range is the same as calibration in single range. To achieve
independent ranges, the computer scales the 3 outputs using the ranges keyed in by the operator.
7.10. Calibration Quality After calibration is complete, it is very important to check the QUALITY of the calibration. The
calibration of the M200AH involves balancing several sections of electronics and software to
achieve optimum accuracy, noise, linearity and dynamic range.
The slope and offset parameters are similar to the span and zero pots on an analog instrument.
Just as in the analog instrument, if the slope or offset get outside of a certain range, the
instrument will not perform as well.
The slope value will be slightly different on the NO and NOX channels. This is due to slight
differences in pneumatic resistance in each pathway. If the slopes are significantly different,
there is a calibration error or a cross port leak in the switching valve. If there is a sudden change
in slopes after a calibration, that usually indicates a change in reaction cell pressure. Check the
Troubleshooting Section 9.
The offset value gives information about the background signal level. Check the observed offset
value against the factory value in Table 2-1. If significantly higher, check Section 9.1.6.
Increasing readings are a predictor of problems.