Hi,
I am using a U6 device to measure the voltages across a set of four supercapacitors that charge for around 40 seconds at 26mA, and discharge for about half a second at 133mA, with a supply voltage of 3.6V.
This was working fine, however when I tested the setup yesterday , I noticed that the 4 AIN channels all read around 4.5V with inconsistent fluctuations in the value. I tested the voltages across my supercapacitors to be 3.6V, so these AIN readings didn't line up with the actual voltages. On further testing following the AIN troubleshooting guide, the DAC output was reading 0V when I tested it with a multimeter regardless of what I set it to on LJControlPanel, and the AIN channels would continue to read 4.5V thereabouts when connected directly to DAC0 or DAC1 by a jumper wire. One thing to note however is that the FIO channels appear to work fine still for reading my digital inputs.
I was wondering if this is a configuration issue with the settings on the U6 i am using, or more likely a hardware issue?
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If you were previously testing with your capacitors connected I would recommend you remove all connections so that you are only testing with USB plugged into the U6.
I would suggest you check the voltage between VS and GND is 5V using a DMM then try testing the DAC and AIN again. Make sure you have solid electrical connections anytime you test:
https://labjack.com/support/app-notes/screw-terminals
If VS is not within the range 4.75-5.25V then the U6 is not being properly supplied and that could be part of your issue. If VS looks good and you are still having issues with the DAC and AIN then there is likely a hardware issue.
I have re-tested with no external components connected, and can confirm that VS to GND reads 5V, and the DAC readings are now functioning. However the AIN channels still are hovering at the values before, even when connecting DAC to AIN and GND to AIN (seperate tests), i have attached a screenshot of the values they are hovering at, which are the same for all of the tests I conducted.
You could try our factory reset SPC jumper and upgrading firmware and see if that fixes anything:
https://labjack.com/support/datasheets/u6/hardware-description/spc
Otherwise, I would recommend requesting a device repair:
https://labjack.com/about/returns