At 09:30 PM 6/14/2005 +0300, you wrote:

>On Tue, 14 Jun 2005, Spehro Pefhany wrote:
>
>>How about not updating the display unless the difference from the displayed
>>value is > x,  (and set x = 1) ?
>
>In that case, how do you adjust the value precisely (assume it has to be 
>adjusted to the nearest LSB with a screwdriver and a trimmer, the display 
>shows 125 and you need to adjust 126). Exercise in frustration ?

Yes, indeed, unless you have a bypass for calibration.

>Low pass filtering is the only viable solution. A display should not 
>change more than 4 times per second if someone is to make sense of it 
>anyway, slower for most physical values. Usually you can low pass enough 
>to achieve this since ad frame rate is often hundreds of times faster than 
>this. Low pass with 8 or more steps is usually drastic enough.
>
>Peter

Depends. I've has some applications where a simple LPF would never do the
trick.

Large process variable variation (due to constraints on the actuator) and
excessively fine display resolution (customer imposed constraint) and
an integrating process.

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
->> Inexpensive test equipment & parts http://search.ebay.com/_W0QQsassZspeff


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