Too much noise with an analog temperature sensor connected via RSE Configuration

[Trekev]

I have connected a Vaisala HMP-155A temperature and RH sensor to an NI 9205 module via an RSE connection.  I am getting reasonable temperature and RH
values, however the data is extremely noisy.  The temperature is ranging +-0.8C.  Any ideas on how to reduce noise?  I've tried both an RSE connection and a NSRE connection.

[SnowMule]

Go differential, run a separate ground wire to the sensor.  If the noise is common, the noise on the two lines will subtract each other out. 

Shielding's another option.  Pay attention to grounding to eliminate ground loops. 

http://www.planetanalog.com/document.asp?doc_id=527768

Or do both.

[Trekev]

Attached is an image of the noise when run through NI MAX

[Henrik_Volkers]

Samplerate?
Have you tried to mean multiple (1000?) samples over a second or minute?
Most temperature measurements are usually quite slow... Noise is everywhere ..
Ah.. And take a deep look into the specs to find out what you might expect...