I'm trying to use the AIN via the DB15 connector to a LabJack U3-HV. If I'm understanding correctly from Sect 2.5 of the manual:
https://labjack.com/support/datasheets/u3/hardware-description/fio
...I should be able to do this using any of EIO0 to EIO7. But I can't seem to get it to work. The AIN0-3 all work fine on the screw terminals on the side of the U3. But I can't get it to work through the DB-15 connector. I've even tried attaching a test voltage to each EIO pin in turn, then scanning through all the possible channel #s in my program. But I just can't see the voltage appearing in the program while monitoring (which is the eFunctions.vee program, by the way, image attached.) All the digital I/O works fine. Maybe I'm missing something simple here. Any ideas? Thanks in advance!
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In your screenshot it looks like it is working. You request a read from FIO4 (FIO4-EIO7 can be used as low-voltage analog inputs with channel numbers 4-15), and it returns no error and a floating point value of 0.4 volts. If you jumper FIO4 to GND you should see it read near 0.0 and if you jumper FIO4 to VS you should see it read near 2.4 volts (can't go to 5).
I agree, it looks like it should work. Unfortunately it doesn't seem to. In that screen shot, I was applying +4V to FIO4, not 0.4V. So from what you say, it seems like I should have been reading 2.4V (the maximum). But it didn't seem to matter what voltage I applied, it never changed. I tried the same thing on a different U3-HV unit as well, but with the same results.
Please let me just check to make sure I'm understanding correctly: in order to perform AIN from the DB15 EIO0 to EIO7, according to Table 2.11-1 and Table 2.6.1-2, I should use the DB15 pins and channels shown in the attached table image. This is what I'm trying, but it doesn't seem to be working. Is this correct? FYI, these designations do work for digital I/O (eDI and eDO), just not for AIN. Please let me know what you think. Thanks!
FYI, from the LJ Control Panel, I'm seeing the AIN working correctly, that is reading small analog voltages (0 - 2.4V) on any of EIO0 to EIO7. Just not from my VEE program. Strange...
I just exited from the LJ Control Panel and tried it again. Now AIN works on all the EIO pins on theDB15! I don't understand. I tried this last night and today repeatedly with the same results. Now it seems to work. Could it be an intermittency? I don't think I'm losing my mind...but you never know!
In any event, all is well for the moment. Sorry if I waste your time. Thanks for you help!
It would expect it not to work while LJControlPanel is running, you should only have 1 U3 related program running at a time, but I would have expected you to get an error from your open call if LJCP already had the U3 open.
Let us know if you see any further unexpected behavior.
I wasn't running LJControlPanel at the same time, but yes,that would be a definite no-no!I have seen occasional instances of quirky behaviour now and then on the U3, but they usually go into hiding quickly and resist further analysis ... leaving me wondering if I'm the quirky one.
The good news for now is that everything appears to running fine. I really appreciate your help and the prompt turn-around with suggestions. Have good weekend!