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Model 9110T NOx Analyzer Data Acquisition System (DAS) and APICOM
Teledyne Analytical Instruments 172
7.1.3.3. Editing DAS Parameters
Data parameters are types of data that may be measured and stored by the DAS. For each TAI's analyzer
model, the list of available data parameters is different, fully defined and not customizable. Appendix
A-5 lists firmware specific data parameters for the 9110T. DAS parameters include data such as NO
x
,
NO and NO
2
concentration measurements, temperatures of the various heaters placed around the
analyzer, pressures and flows of the pneumatic subsystem and other diagnostic measurements as well as
calibration data such as stability, slope and offset.
Most data parameters have associated measurement units, such as mV, ppb, cm³/min, etc., although
some parameters have no units (e.g. SLOPE). With the exception of concentration readings, none of
these units of measure can be changed. To change the units of measure for concentration readings, see
Section 5.4.3.4.
Note DAS does not keep track of the units (i.e. PPM or PPB) of each
concentration value. Therefore, DAS data files may contain concentration
data recorded in more than one type of unit if the units of measure were
changed during data acquisition
Each data parameter has user-configurable functions that define how the data are recorded which are
listed in Table 7-3:
Table 7-3: DAS Data Parameter Functions
FUNCTION EFFECT
PARAMETER
Instrument specific parameter name.
SAMPLE MODE INST: Records instantaneous reading.
AVG: Records average reading during reporting interval.
SDEV: Records the standard deviation of the data points recorded during the reporting interval.
MIN: Records minimum (instantaneous) reading during reporting interval.
MAX: Records maximum (instantaneous) reading during reporting interval.
PRECISION 0 to 4: Sets the number of digits to the right decimal point for each record.
Example: Setting 4; “399.9865 PPB”
Setting 0; “400 PPB”
STORE NUM.
SAMPLES
OFF: Stores only the average (default).
ON: Stores the average and the number of samples in used to compute the value of the
parameter. This property is only useful when the AVG sample mode is used. Note that the
number of samples is the same for all parameters in one channel and needs to be specified
only for one of the parameters in that channel.
Users can specify up to 50 parameters per data channel (the 9110T provides about 40 parameters).
However, the number of parameters and channels is ultimately limited by available memory.
Data channels can be edited individually from the front panel without affecting other data channels.
However, when editing a data channel, such as during adding, deleting or editing parameters, all data for
that particular channel will be lost, because the DAS can store only data of one format (number of
parameter columns etc.) for any given channel. In addition, a DAS configuration can only be uploaded
remotely as an entire set of channels. Hence, remote update of the DAS will always delete all current
channels and stored data.