Signal conditioning

kash75 · Oct 8, 2004

I am using thermocuple card 1769-IT6 for Micrologix 1500. I am getting some noise due to the some of the AC lines that is bunched with the TC wirings (main problem). There is not a function in the 1500 that allows me to put filtering on the TC signals. Does anybody has any suggetion on how to create some sort of filtering for this types of problems.

Sam

Tom Jenkins · Oct 8, 2004

Try throwing a capacitor across the T/C leads. I've used a 220 micro-Farad successfully with other T/C devices.

Bob O · Oct 8, 2004

Sam,

I am not sure if this will help or not.

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Bob O.

kash75 · Oct 8, 2004

Bob:

I have tried that, I still get noise on the TC due to the contactors going on/off.

Thanks

Mickey · Oct 9, 2004

This works for me, to filter numerical values.

((raw value - filtered value) times ( X )) plus (filterd value)=filtered value

The smaller the value of X the more filtering

Peter Nachtwey · Oct 9, 2004

A digital filter doesn't always work.

Sometime the noise spike are very severe and no averaging technique will work. In this case I recommend over sampling. Take a reading every 1 and sort them in an array. After you have your 20 samples then use the 10th one. It will be the median value. This way a few bad noise spikes will not affect your data.

dandrade · Oct 11, 2004

It awoke reveal it a technique in the programming, against they EMI

Always, I group similar components in sequence of a byte in the card of output. Compares the byte, always when modify shoot a timer of freeze, that controls ENABLE of atualization of the analog elements.

Signal conditioning

kash75

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Tom Jenkins

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Bob O

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kash75

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Mickey

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Peter Nachtwey

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dandrade

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