Stable display readings

[MogaRaghu]

When displaying analog values from sensors like Temperature probes ( PT 100 ), flowmeters and pressure values it is quite irritating to see the second decimal or at times even the first decimal point rolling rapidly.

Most times it is due to overriding noise on the signal. But even when we follow strict guidelines with respect to shielding, grounding, differential mode inputs I still cannot completely eliminate this.  And all my channels have low pass filters to remove the AC line noise and I also resort to a moving average of atleast 5 samples.  One would expect  a channel like Room Temperature to be stable - it simply cannot vary  that fast .

What I want to see on the screen is a display that is as steady as an analogue meter. Is there any proven method in software apart from moving average to do this ? Reducing the display precision would be one another way - but then it also reduces the resolution of the required display.

Thanks

Raghunathan

[devchander]

Raghunathan,

One point I would like to put forth: Setting the optimal range for your measuring device, so that the parameter is measured with a pretty good resolution.

For ex, if you anticipate temperature variation in range of 10 - 60 deg C, it would be advisible to keep the high and low limit correspondingly.

This would improve your resolution and give a pretty stable readings