[wxsig] RE: Question on T238 humidity

[Will Beals]

Russ:

Unfortunately, no.  There is only one 1-wire ID for both the temperature
sensor and the analog inputs that are used to digitize the data from the
humidity sensor.  When the ID gets erased, all data gets lost.

That brings up a boundary case I'm not sure I've tested.  If you set up the
T238 to use the humidty sensor as the official temperature sensor then
delete it, I hope I revert back to whatever was selected for the "normal"
DS18x20 sensor as the backup.  If temperature suddenly goes away completely,
you may need to rediscover whatever temperature sensor you have.

will
-----Original Message-----
From: Russ Chadwick [mailto:russ at wxqa.com] 
Sent: Sunday, June 11, 2006 8:28 PM
To: will at beals5.com
Cc: 'TAPR Weather Station SIG Mailing List'
Subject: RE: Question on T238 humidity

Will,

Thanks for the info.  If I do this, will I still be able to use the
temperature from the DS2438 in the humidity module?

Russ  KB0TVJ

-----Original Message-----
From: Will Beals [mailto:will at beals5.com]
Sent: Monday, June 12, 2006 2:08 AM
To: 'Russ Chadwick'
Cc: 'TAPR Weather Station SIG Mailing List'
Subject: RE: Question on T238 humidity


Russ:

(posting to WXSIG in case other folk may want to know too)

I must confess that I don't have a way to stop looking at a sensor.  If the
sensor no longer responds I don't broadcast data and give the opportunity to
remove its ID from the tables.  If a sensor gets replaced I give the
opportunity to reprogram in a new one, but I don't have a way to stop
reporting data from a sensor that is still there and giving (what appears to
be) valid data.

I seem to remember that question coming up on the wxsig reflector a long
while ago.  I went back and looked at my software and the the request was to
be able to remove the IDs of a sensor that was no longer present.  That
feature is incorporated.

I can suggest the following though.  Start the normal "sensor setup"
sequence.  When you get to the option to discover the humidity sensor,
unplug the 1-wire bus from the T238, then tell it to discover the humidity
sensor.  It won't find it and offer to erase the ID.  That should work.

will

-----Original Message-----
From: Russ Chadwick [mailto:russ at wxqa.com]
Sent: Sunday, June 11, 2006 10:46 AM
To: will at beals5.com
Subject: Question on T238 humidity

Will,

In the T238, is there a way to remove the humidity measurement from what is
sent and still keep the temperature from the DS2438.  I have a situation
where the humidity measurement is stuck at 100% and that's what is
transmitted even though it's much drier than that.

http://www.findu.com/cgi-bin/wxpage.cgi?call=KB0TVJ-8!Cody

Russ   KB0TVJ