01-30-2007 06:01 PM
01-31-2007 06:35 PM
02-01-2007 11:15 AM
02-01-2007 12:13 PM
02-01-2007 02:06 PM
02-02-2007 11:35 AM
02-02-2007 12:08 PM
02-02-2007 12:14 PM
02-06-2007 06:35 PM
I've been working with Ken on the data acquisition system.
Replacing the MIO-PCI-16XE-50 board with a different MIO-PCI-16XE-50 board seemed to work. However, I decided to self-calibrate the new board prior to re-calibrating a couple of channels. I calibrated it once with the SCXI chassis powered, then read that all inputs to should be removed and calibrated it again after I turned the power off to the SCXI chassis. I then went to see if the self-calibration had any effect on the values and discovered that they no longer functioned. A check of the first two channels showed that the signal started at a low voltage level and continued to climb, presumably until it was out of range. This is precisely what had happened to one of the channels on the last board. Unfortunately, I seem to have wiped out multiple channels where it had been only one before.
The only major change between the time I self-calibrated the first board and the time I self-calibrated the second board was the addition of a relative humidity sensor. The sensor did not come with a plug and I had to wire it up following the directions. After I wired it up, I ran some tests to see if I should leave the relative humidity isolated or whether I should ground it. When it was isolated it affected the other channels detrimentally so I wired that chassis to the chassis ground. I don't remember it causing a problem previously, but now I wonder if I am inadvertently sending a large voltage spike to the DAQ board.
I would appreciate any help solving this problem. I need to get things running and I don't want to keep damaging stuff.
Karol
02-07-2007
03:36 PM
- last edited on
07-16-2025
02:15 PM
by
Content Cleaner
Hello Karol,
If you suspect that the PCI-MIO-16XE-50 is damaged, you can check it using the DAQ Diagnostic Utility. This will test each analog input channel by reading from an onboard precision voltage reference. Otherwise, if it passes this test, something may have been incorrect in either the signal connections or the program itself. I was a bit confused about why you attempted to calibrate any channels when the SCXI chassis was off. There should not be any reason for doing so.
As far as connecting your relative humidity sensor, generally it is not a good idea to connect the ground of your sensor to the ground of your measurement device. This creates a ground loop which can introduce significant error into your readings. For a good summary of which terminal configurations to use with different types of signal sources, please refer to Table I in the tutorial Field Wiring and Noise Considerations for Analog Signals.
I hope this information helps. Let me know if you have any questions about what I've described.
Best regards,