Noisy thermocouple signal with SCXI-1125

[Angelantoni]

Hi all

Am using SCXI -1125, with 1328 terminal blocks, I have set the filter to 4hz in the signal conditioner. Am using 256 T type thermocouple, with 1 sample per channel at a very low sampling rate "1Hz".

Am receiving lot of noise in the signal, aprox +/- 1deg. But there are other channels which are very stable with hardly 0.2deg variation. I have tried connecting the negative of the noisy signal to ground, but with no results. Can anyone give some input on this?

Thanx a lot

Arun

[Angelantoni]

Hi Again

I got  why the channels are noisy, It is because the lowpass filter is not getting enabled, am using the channel property node to set the "lowpass cutoff frequency" and "Enable filter". but when i read back the same, the properties are not set.

But the property are set correctly when i use MAX.

Can anyone tell me what the problem might be

Thanx

Arun

[Ryan_V[DE]]

Arun,

Are you sure you are setting these properties correctly? Before modifying any of these properties, you must specify the active channels. Please take a look at the attached example program. It sets the active channels to all channels in the task and then sets the auto-zero mode. A similiar process should work for enabling the filter and setting the cutoff frequency.

Hope this helps!