[time-nuts] Tbolt temperature sensor

Bruce Griffiths bruce.griffiths at xtra.co.nz
Thu Feb 5 04:16:07 UTC 2009


Steve Rooke wrote:
> 2009/2/5 Magnus Danielson <magnus at rubidium.dyndns.org>:
>   
>> Tom Van Baak skrev:
>>
>> I don't think 0,25 C resolution is worthless, but it can still do good work.
>>
>>     
>
> Sorry for the heavy editing but I have been following this thread
> closely. Now if the temperature circuit only reacts to changes of
> 0.25C then doesn't that represent quite a bit of hysteresis in the
> system, and is liable to cause overshoot, or am I missing something
> here.
>
> 73, Steve
>   
According to the data sheet the readout resolution in normal 9 bit mode
is actually 0.5C not 0.25C.
The firmware appears to offset the temperature output data by  -0.25C
from the DS1620 reading.
The high resolution mode has 12 bits resolution or about 0.0625C.
Conversion time from temperature to digital is about 750ms.

Bruce



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