LabJack Error #1007
3 replies to this topic
Posted 06 May 2013 - 09:12 PM
Hi, We have a Labjack U3-HV and are using it to plot pressures in a pipe using pressure transducers.. I have the test setup as shown below, with 2 transducers to measure 2 different parts of the system. It seems to work fine 4/5 times, but every now and again it fails half way through the test with the error message "Labjack Error #1007: LabJack not found occured at LJUD_OpenLabJackS.vi" Do you have any idea's what could cause this error? It looks like it could be the USB connection being lost, but I can't see how this would occur? It's annoying as it takes about 4 hours to set up each test, only for the LabJack to let us down! Any help would be appreicated, thanks.
Posted 07 May 2013 - 08:59 AM
From what I understand, you have a test that takes 4 hours to prep. Then you run the test and the U3 needs to stream 2 channels at 25 Hz for just a couple minutes. About 1 out of 5 such tests, you get errorcode 1007 halfway through (~60s) and thus don't collect all your data. Without doing all your system prep and actually running your test, if you just run LJStreamUD for a while, does it have any problems? How about if you repeatedly run it for a couple minutes each time? While troubleshooting, one immediate way to reduce data loss might be to enable the watchdog and switch to command/response mode. Are you using LabVIEW, or running executables?
Posted 07 May 2013 - 09:49 PM
Thanks for your reply.. Yes you're right... 4 hours to prep, then around 1 minute to run the test. We don't need incredible accuracy which is why we chose 25Hz, and we have 2 channels (each recording a different section of pipe). Before we run each test, we do a trial run where we start the LabJack and let it run for around 1-2 minutes, with no errors, we can only get it to fail during testing? I wondered if it could be caused by some sort of system shock (we let pressure build in the pipe, then it fails when we suddenly release the pressure). I've attached an image below to show what a good set of results look like. All of our testing is being done in LJStreamUD.exe, with results being exported to a text file. It's quite a basic setup as none of us are completely knowledgable on computer programming.. so I have no idea what you mean by "enable the watchdog and switch to command/response mode"??
Posted 08 May 2013 - 03:54 PM
I'm the best person to help on this, and gone the rest of the week, so might not be able help more until Monday. I can get into more detail on the "enable the watchdog and switch to command/response mode" idea if you want to pursue it. It does not prevent the problem, but potentially allows the U3 to recover automatically, so you would have a perhaps 10 second gap in your data rather than losing all data. Since the problem only happens when your system goes through its test, it does suggest that some sort of transient is caused by the system, traveling to the USB host on your computer, and causing the host to "lose" the U3. Does your system have any motors, mechanical relays, solenoids, or electromechanical valves that could be causing an arc? What is the minimum required to regain communication with the U3? If you just close LJStreamUD and run LJLogUD does it talk to the U3? Or do you have to power-cycle the U3? For that matter, you might try using LJLogUD for your test rather than LJStreamUD. If the stream has a problem the stream gets stopped until you restart it. With LJLogUD, if there is a temporary problem it will start collecting data again as soon as the connection is restored. It might not be convenient, but would be nice to try and determine if the transient is conducting up the signal wires or radiating directly to the U3 or computer. That would require running some system pressure tests with the 4 AIN/SGND wires not connected to the U3. If the transient is coming through the wires, you could try resistors, capacitors, and TVS diodes to attempt to stop it. The ground for both your sensors is the same, so you only need 1 ground wire. That leaves 3 wires to try and protect: SGND, AIN0, and AIN1. I can see a network of series resistors with parallel caps and diodes. Can work on more detail next week.
0 user(s) are reading this topic
0 members, 0 guests, 0 anonymous users