Random Numbers

I have a DL340 which takes the 4-20 ma signal from WI127( Scale) analoge bioard.when scale shows 0 Kg -PLC shows high random numbers when I monitor that register with HHD.This is not happening when there is something in the silo.IS something wrong with the analoge module ?

Thanks

Sounds more like the scale is not calibrated with the analog board and is sending less than 4ma. When this occurs if you are scaling to engineering units, you will be outside of your range and then "wrapping" around. Check the zero point of your scale and then put a 4-20ma transmitter on your analog card and check the zero point of the card. The reading should match. If not, then you will have to correct it by changing the sclae zero point or go into the programming and change it there.

I changed the AI modual and calibrate the scale for 4-20 ma but still is the same.
I am thinking that noise can cause this issue .or the Analouge board inside the scale sending this .
any ideas?

I changed the AI modual and calibrate the scale for 4-20 ma but still is the same.

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Yes, but did you check the signal for the zero point of the scale against the zero point of the card?

4 ma is not alsways 4 ma. It should be, but rarely are two pieces of equipment calibrated the same "out of the box." Even equipment that is supposedly calibrated to ANSI or ISO standards may not read the same when it is installed in the field.

I suppose that it could be noise, but you state that:

This is not happening when there is something in the silo.

Click to expand...

This leads me to believe that the zero points of the two devices do not match...