Load Cell Intrerference
Steve,
Below is a link to a very good and detailed document on RFI. It is written by a Ham radio operator and goes into great detail. I believe the simple answer to your problem can be found on page 5. I have used this method before with good results. It involves of course using twisted shielded wiring and installing the circuit in a grounded enclosure. Then make sure all the grounds and shields to the circuit are grounded on the OUTSIDE of the enclosure. This way you do not "invite" the RFI inside to your circuit instead it is "drained" to ground. If this does not work this document has plenty of other ideas.
Good Luck
Allen
http://www.audiosystemsgroup.com/RFI-Ham.pdf ■
Load Cell Interference
I have the need for a custom analog circuit were load cell signal is amplified. I have built the amp on a ground plane and found the circuit to be stable and free of noise. The load cell cable is shielded and properly driven as recommended in the IC application notes and I have input filtering to the amp.
Our plant personel use mobile radios and I find that the transmissions within a 12' radius are picked-up and recified in the amp. The shield is as it is so i am looking at the input filtering.
My questions are:
1) can anyone reccommend RC values or cut-off freq for this application on the input filter?
2) Does this application require power dissapating attenuation?
3) Should a shielded cable prevent this interference on it's own?
Thanks,
Steve ■