Load cell amplifer signals

[Martin.Griffiths]

Hi All, 

I'm trying to build an app to read a signal from a RS load cell & amplifier using a USB6210 daq card. I'v tried SE & Diff connections, and I see a change in signal when I apply a load, however it's not quite what I expected (see attached screenshots from MAX).

I'm supplying an external 5V to the amplifer, so with no load expect to see approx 3V from the amp - this works OK. With a load applied I expected to see a constant voltage drop, however I seem to be getting an unstable, spiked drop in voltage.

Any ideas why this is happening, any help would be much appreciated.

Thanks,

Martin 

Link to RS load cell & amp spec sheet: 

http://docs-europe.origin.electrocomponents.com/webdocs/0099/0900766b80099349.pdf 

[Henrik_Volkers · Accepted solution]

Looks like a 100Hz hum ..... grounding and shielding and a clean powersupply for your amp??

Any switched power devices (powersupplies, converter, ....) nearby (shure your PC 😉 ?? Electronic ballasts for modern energy saving light or dimmer ?? 

[Martin.Griffiths]

Thanks Henrik, using shielded cable solved the noise problem. I also changed the supply to the amp to give 12V instead of 5V, it seemed 5V was just below the operating range of the amp.

Thanks again.

Martin  

[Unicon123]

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