lowpass filter help for thermocouple reading

[Tim_C.]

Hello I have an old legacy E-Series AI-16SE 12bit 500KHz PCI card. I am attempting to setup a temperature reading test program. I will have the E-Series connected to a SCB-68, which will have five T type thermocouples connected. I realize this is not the best test setup but it is an attempt at a quick setup on a bench so hopefully any noise interferance will be minimal. I will be using LV 8.2 professional development. I was wondering if I setup a software based lowpass filter if that would be helpful in this situation? If so can someone show an example the has a cutoff freq for 2Hz? I am unfamilular with all the settings of the lowpass filter VI and some guidance would be much appreciated. Thanks in advance Tim C.

[RobCole]

Just a thought on an alternative...

While  a low pass filter may help (if you have noise), the approach that we use is to acquire the data at 1kHz and then average 100 samples (so we get data 10 times a second). This has worked exceptionally well for us.

     Rob

[johnsold]

Tim,

Rob's idea is probably what you should try first.  It is in effect a low pass filter with about a 10 Hz corner frequency.

If you find that you have strong power line frequency interference, you may need to do more aggressive signal conditioning.  Especially watch out for ground loops.

Lynn