# Ph meter signal smoothing

**URL:** <https://forum.inductiveautomation.com/t/ph-meter-signal-smoothing/12249>\
**Category:** Ignition\
**Created:** [October 17, 2016, 9:47pm UTC](https://forum.inductiveautomation.com/t/ph-meter-signal-smoothing/12249 "2016-10-17T21:47:16Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![davidkr](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@davidkr](https://forum.inductiveautomation.com/u/davidkr)\
**Post date:** [October 17, 2016, 9:47pm UTC](https://forum.inductiveautomation.com/t/ph-meter-signal-smoothing/12249/1 "2016-10-17T21:47:16Z")

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I am reading a ph probe 4-20ma signal that changes as much as .75 every 500 msec which makes it difficult to read. I would like to buffer this output to reflect a moving 3-5 second average. How would I go about doing this?

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**Author:** ![Curlyandshemp](https://avatars.discourse-cdn.com/v4/letter/c/bcef8e/32.png) [@Curlyandshemp](https://forum.inductiveautomation.com/u/Curlyandshemp)\
**Post date:** [October 18, 2016, 4:06pm UTC](https://forum.inductiveautomation.com/t/ph-meter-signal-smoothing/12249/2 "2016-10-18T16:06:26Z")

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This is typical in PLC applications:

FV=FV+C(NV-FV)  
Where:  
FV= Filtered value  
C= constant (range 0-1) The smaller the number the more dampening.  
NV= New Value