Hi,

I have built a switching power supply that also does
temperature control of a CCD sensor using a Peltier module,
a DS1820 and a PID algorithm programmed into a PIC.

At times I have false readings from the DS1820 sensor.

I understand this may be caused by the somewhat noisy
environment, the fact that the (filtered) Peltier supply
transits on the same 25-wire shielded cable (no separate
shield for the 1-wire bus). However this happens rarely,
maybe once in 2000 measurements or less.

I have not found much on the subject of noise sensitivity
for this bus; the data sheets says the pull-up resistor
should be around 5 KOhms, which is vague.

For the time being I am exluding by software wrong readings,
but this is half satisfactory: could anyone suggest how to
improve the reliability?

* Xrobert.soubie@free.frX (veuillez supprimer les "X")
* http://www.astrosurf.com/soubie
* Au royaume des aveugles, les borgnes sont mal vus... - P.Dac

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