DRdaq noise on signal
DRdaq noise on signal
Hi
using a DrDaq to log voltage data but when setting up the system we get noise on the signal that cannot be removed.
if we try shorting the input connectors i would expect to see zero volts but the noise moves from 0 to 30mv
the signal we are measuring is in the range zero to 0.5 v
any solutions or do we have a faulty Dr Daq
thanks
Andy
using a DrDaq to log voltage data but when setting up the system we get noise on the signal that cannot be removed.
if we try shorting the input connectors i would expect to see zero volts but the noise moves from 0 to 30mv
the signal we are measuring is in the range zero to 0.5 v
any solutions or do we have a faulty Dr Daq
thanks
Andy
Re: DRdaq noise on signal
Hi
Got a second DrDaq and it shows the same symptoms
Is my laptop that is generating the noise? or the usb power supply from the laptop
Thanks
Got a second DrDaq and it shows the same symptoms
Is my laptop that is generating the noise? or the usb power supply from the laptop
Thanks
Re: DRdaq noise on signal
No
Tried it on batteries, but no difference,
Any more advice
Thanks
Tried it on batteries, but no difference,
Any more advice
Thanks
Re: DRdaq noise on signal
Can you post a psdata file showing the noise, we can then look at the settings and data in context.
Martyn
Technical Support Manager
Technical Support Manager
Re: DRdaq noise on signal
Hi data recording uploaded as file atachment
Test run with noise
voltage input is on the top line and had the input leads shorted together, when using it with the measuring source we get the same level of noise that interferes with the signal we are trying to look at.
Thanks
Test run with noise
voltage input is on the top line and had the input leads shorted together, when using it with the measuring source we get the same level of noise that interferes with the signal we are trying to look at.
Thanks
- Attachments
-
- test2.plw
- test run with noise
- (21.9 KiB) Downloaded 222 times
Re: DRdaq noise on signal
the range is o to 30 mV on the recording. the noise seen is roughly 20mV when you have the scope running, same with the pico log.
the measurement we are looking at is from zero to 0.5v. that relates to the source, a force gauge that reads zero to 5kg.
the noise is almost as large as the changes we are looking at when taking a reading.
Thanks
the measurement we are looking at is from zero to 0.5v. that relates to the source, a force gauge that reads zero to 5kg.
the noise is almost as large as the changes we are looking at when taking a reading.
Thanks
Re: DRdaq noise on signal
But which range of the four for the DrDaq are you using
±1.25 V, ±2.5 V, ±5 V, ±10 V
As the scope is 8 bits you have 255 steps across the specified range, so if you are on the 10V scale this would give a step resolution of 78mV, on the 1.25V range you would get 10mV.
±1.25 V, ±2.5 V, ±5 V, ±10 V
As the scope is 8 bits you have 255 steps across the specified range, so if you are on the 10V scale this would give a step resolution of 78mV, on the 1.25V range you would get 10mV.
Martyn
Technical Support Manager
Technical Support Manager
Re: DRdaq noise on signal
+/- 1.25v but no change when you use the other ranges
Thanks
Thanks
Re: DRdaq noise on signal
The noise looks to be within the ±3% accuracy quoted for the oscilloscope channel of the DrDaq. As this is gaussian noise it can be removed by using a software moving average filter, resolution enhancement in Picoscope software.
Martyn
Technical Support Manager
Technical Support Manager
Re: DRdaq noise on signal
Hi
Thanks
looks like a soulution for now, possibly plot the average reading over 10 - 20 samples to smooth out the curve but problen is that i am looking for small transiant changes in the force.
i will keep experimenting see if i can get any better results
possibly have to resort to a more expensive 24 bit model of A to D
Thanks for your help
Thanks
looks like a soulution for now, possibly plot the average reading over 10 - 20 samples to smooth out the curve but problen is that i am looking for small transiant changes in the force.
i will keep experimenting see if i can get any better results
possibly have to resort to a more expensive 24 bit model of A to D
Thanks for your help