Software Operation; Adaptive Filter - Teledyne T100 Instruction Manual

Theory Of Operation

9.7. SOFTWARE OPERATION

9.7.1. ADAPTIVE FILTER

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The instrument's core module is a high performance, X86-based microcomputer running
Windows CE. Inside Windows CE, special software developed by Teledyne ML
interprets user commands from the various interfaces, performs procedures and tasks,
stores data in the CPU's various memory devices and calculates the concentration of the
gas being sampled.
Windows CE
API FIRMWARE
Memory Handling
DAS Records

Calibration Data

System Status Data

Measurement
Algorithms
Figure 9-24:
The T100 SO analyzer software processes sample gas measurement and reference data
2
through an adaptive filter built into the software. Unlike other analyzers that average the
sensor output signal over a fixed time period, the T100 calculates averages over a set
number of samples where each sample is 1 second. During operation, the software
automatically switches between two filters of different lengths based on the conditions at
hand.
During conditions of constant or nearly constant concentration the software computes an
average of the last 240 samples or 240 seconds. This provides the calculation portion of
the software with smooth, stable readings. If a rapid change in concentration is detected,
the adaptive filter switches modes and only averages the last 20 samples or 20 seconds.
This allows the analyzer to respond to the rapidly changing concentration more quickly.
Once triggered, the short filter remains engaged for a fixed time period to prevent
chattering.
Two conditions must be simultaneously met to switch to the short filter. First the
instantaneous concentration must exceed the average in the long filter by a fixed
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Teledyne ML - T100 UV Fluorescence SO2 Analyzer
Instrument Operations
Calibration Procedures

Configuration Procedures

Autonomic Systems

Diagnostic Routines

Interface Handling
Sensor input data

Display Messages
Touchscreen

Analog output data

RS232 & RS485

External Digital I/O

Basic Software Operation
PC/104 BUS
INSTRUMENT
HARDWARE
PC/104 BUS