Teledyne API T802 Paramagnetic O2 Analyzer Operation Manual Principles of Operation
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12.5.8. SOFTWARE OPERATION
The T802 Analyzer is at its heart a high performance, VortexX86-based
microcomputer running Windows CE. Inside Windows CE special software
developed by Teledyne API interprets user commands via the various interfaces,
performs procedures and tasks, stores data in the CPU’s various memory devices
and calculates the concentration of the sample gas.
Windows CE
API FIRMWARE
Analyzer Operations
Calibration Procedures
Configuration Procedures
Autonomic Systems
Diagnostic Routines
Memory Handling
DAS Records
Calibration Data
System Status Data
Interface Handling
Sensor Input Data
Display Messages
Touchscreen
Analog Output Data
RS232 & RS485
External Digital I/O
Measurement
Algorithm
ANALYZER
HARDWARE
PC/104 BUS
PC/104 BUS
Linearization Table
Figure 12-15: Basic Software Operation
12.5.9. ADAPTIVE FILTER
The T802 software processes the O2 concentration signal after it is digitized by
the motherboard, through an adaptive filter built into the software. Unlike other
analyzers that average the output signal over a fixed time period, the T802
averages over a set number of samples, where each sample is 1 second. This is
technique is known as boxcar averaging. During operation, the software
automatically switches between two different length filters based on the
conditions at hand. Once triggered, the short filter remains engaged for a fixed
time period to prevent chattering.
During conditions of constant or nearly constant concentration the software, by
default, computes an average of the last 60 samples or 1 minute. This provides
the calculation portion of the software with smooth stable readings. If a rapid
change in concentration is detected the filter switches to 10 samples or 10
seconds measurement moving average to allow the analyzer to respond more
quickly.
07275B DCN6418