Hello!
Recently we have acquired a L7-Pro. I had to do some previous measurements of the noise of the device. To do that I just attached a 1kohm resistor from the AIN0 to ground. I connected the L7-Pro to my laptop using the USB connector and I used the "LJStreamM" to gather 15-20 seconds of data. Later on I processed that data to obtain the noise and I obtained the figure attached. We expected the 50 Hz peak but we cannot explain the 10 Hz peak.
We were at a sample rate of 100k with a gain/range of 4. Maybe you had encountered this peak before.
Thank you for your time.
File Attachment:
.png%3Fitok=PHGBxf6M "EEV Blog Reviews LabJack T7-Pro & Software Tools")
.jpg%3Fitok=B1YcuDFK)
.png%3Fitok=Ybt-OlgU "LabJack + JEDI One Can Create a Powerful Distributed DAQ Ecosystem")
The key thing is to confirm that your overall noise levels are similar to what we document:
https://labjack.com/support/datasheets/t7/appendix-a-3-1
As for why there is a noticeable 10Hz component, my first guess would be perhaps the LED blinking or that could be the interval at which packets are sent over USB or Ethernet.
Do your results look much different with a short from AIN0 to GND? We do our noise tests with 0 ohms.
You are doing 1 channel at 100k, correct?
Are you using the default ResolutionIndex of 0 which equates to 1 in stream mode?
I am not sure what you mean by gain/range=4. Are you using the +/-10V, +/-1V, +/-0.1V, or +/-0.01V range?