[Hai-users] Temp sensors accuracy again.

[Wijoyo Utomo]

HAI temperature and humidity sensors are frequency modulated. The
formula is f = (temp(degF)*4)/30.
 
I once played with microcontroller to drive the circuit and it confirms
the relationship. It is very stable as long as the frequency stable. I
think the instability in the setup is due to the sensor itself, not the
wire length.
 
Rgds,
W. Utomo

-----Original Message-----
From: hai-users-bounces at tssi.com [mailto:hai-users-bounces at tssi.com] On
Behalf Of Brad
Sent: Saturday, January 14, 2006 8:46 AM
To: 'Ken Schumm'
Cc: hai-users at tssi.com
Subject: RE: [Hai-users] Temp sensors accuracy again.



Thanks for the replies Ken. Your explanation makes lots of sense. Hadn't
thought of the wire length issue.

I'm comparing the readings to a $300 Kestrel 4100 Pocket HVAC tool.
Its temp specs are +/- 1.8 degrees.
Humidity specs are +/-  3%

I also have 3 of the Radio Shack gauges, and those and the Kestrel
agrees with each other within a few tenths of each other on temp and
Humidity.

 

 


  _____  


From: hai-users-bounces at tssi.com [mailto:hai-users-bounces at tssi.com] On
Behalf Of Ken Schumm
Sent: Friday, January 13, 2006 4:59 PM
To: Brad
Cc: hai-users at tssi.com
Subject: Re: [Hai-users] Temp sensors accuracy again.

 

Just curious, if your humidity readings are off what are you comparing
them to? I believe the Radio Shack humidity sensor is accurate to +/- 5
%. If the HAI is also +/- 5% the difference between the two could be 10%
and they'd be within specs.

----- Original Message ----- 

From: Brad <mailto:looney2ns at sigecom.net>  

To: 'Wenzel,  <mailto:Guy.Wenzel at capella.edu> Guy' 

Cc: hai-users at tssi.com 

Sent: Friday, January 13, 2006 2:00 PM

Subject: RE: [Hai-users] Temp sensors accuracy again.

 

In my case, the thermostats readings are very accurate; it is the
Temp.Humid sensor's that are off.

The new temp/humid sensors can not be calibrated. The Thermostats can be
if needed.

 


  _____  


From: Wenzel, Guy [mailto:Guy.Wenzel at capella.edu] 
Sent: Friday, January 13, 2006 12:40 PM
To: Brad
Cc: hai-users at tssi.com
Subject: RE: [Hai-users] Temp sensors accuracy again.

 

I have a similar setup with an Omnistat and a Temp sensor in the hallway
near the same room and see the same 3 - 5 degree difference.  I have not
cheeked to see which is more correct.  Does anyone else know if it can
be adjusted or just the thermostat?

 

 


  _____  


From: hai-users-bounces at tssi.com [mailto:hai-users-bounces at tssi.com] On
Behalf Of Brad
Sent: Friday, January 13, 2006 12:19 PM
To: hai-users at tssi.com
Subject: [Hai-users] Temp sensors accuracy again.

 Just installed 3 HAI temp/humidity sensors. Also installed 3 HAI
OmniStats with remote temp sensors. The Thermostat remote sensors and
the Temp/Humidity sensors are mounted on inside walls within 6 inches of
each other, each set in a different room. Temp/Humidity sensors show
temps being 3-5 degrees higher than the thermostats show.

Apparently HAI STILL has not resolved the issue of the Temp/Humid
sensor's being inaccurate.

The Humidity is reading low on them as well. Very frustrating.

Anyone else seeing this?


  _____  


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