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2 pa9: moving average – Hamilton Electronics EPHUM011 User Manual

Page 27

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pH ARC Sensors Modbus RTU Programmer

s Manual (EPHUM011)

624300/01

page 27 / 67

2.6.2 PA9: Moving Average

The pH ARC Sensor provides new pH readings every 3 seconds. One has the possibility to smoothen
the pH reading (PMC1) by means of a moving average applied to the 3-seconds-readings.

PA9 can be applied on 1 to 16 3-seconds-readings. The default value is 2.

Effect of Moving Average (n=1 vs n=16)

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Effect of Moving Average (n=1 vs n=16)

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Figure 2.6.2.1: Comparison of the response of a pH ARC Sensor to a change from pH 5.1 to pH 2.5,

using no moving average (n=1) or a moving average over 16 3-seconds-readings.

Using moving average, the short term signal stability can be improved; on the other hand, the response
time of the sensor increases with increasing moving average. A moving average over 16 samples
results in a response time of at least 48 s.

Note:

 PA9 is applied to both PMC1 and PMC6.