Vigilantplant TDLS8000, User Manual

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<Appendix 5 What Is an Analysis Period?>
App.5-1
IM 11Y01D01-01EN
Appendix 5 What Is an Analysis Period?
The TDLS8000 calculates process gas concentration from a value obtain by integrating the
spectrum data over a given period. This integration period is the analysis period .
Measured values and analog output are updated every analysis period. The analysis period is set
to an optimal value depending on the application and cannot be changed.
On the TDLS8000, you can specify how many analysis periods of spectrum data to calculate the
moving average over. The number of times moving average is taken in a single concentration
calculation is called the average number , and the corresponding time is called average time .
The average number is variable. The average time can be increased by increasing the average
number in order to reduce the influence of disturbance existent in the measurement process.
Even if the average number is increased, measured values and analog output are updated
according to the analysis period, but the analysis responsiveness declines.
The analysis period and average number are set to optimal values according to the process to be
measured before factory shipment. The average number set before factory shipment is called the
basic average number . The final average time is determined as follows.
Average time = (analysis period × basic average number) × average number)
Given a basic average number of 2, the following figures illustrate the moving average ranges
when the average number is changed.
indicates an interval during which a spectrum is acquired and the concentration is
calculated.
l
When the average number is 1
(Average time = analysis period × basic average number × average number = analysis period × 2)
Analysis period
Average time
Measured value and analog output updating
Time
3rd Edition: Jun. 10, 2016-00