04-05-2013 03:44 PM
I am currently trying to pull information I.E. volts amps watts every 0.5 seconds from a Xitron 2801 via RS232 to USB connection. The big problem I am facing is that the program just freezes up at random points during the test and you can't stop the test and does not produce any type of error; if you try to close the app it will say resetting vi:..... and you can't close that window. If you try opening another vi that requires a VISA application it will not work until you reset the computer otherwise there is just an error that pops up that says it can't access the VISA device. The frequency that this happens depends on the computer I am using; the computer I typically write the program on doesn't typically have any problems running this program. I think it has to do with how the Xitron interfaces with LabView. I am hoping someone here may have some experience with interfacing with the Xitron 2801 by sampling data at rates of 1 second or less. Or possibly have had similar problems elsewhere. The Read measurement.vi that is attached is in the repeating loop and the Xitron start.vi is located before the repeating loop which basically initializes the Xitron interface. Also these are written in LV11.
04-08-2013 05:33 AM
The problem might be that your USB hub is cutting power to the converter in order to save power. You can go through USB power settings in the Device Manager and tell Windows not to turn them off.
04-08-2013 08:04 AM
Cross,
Thanks for your suggestion. I just double checked my device manager and power options in the control panel and saw that the USB power down settings are currently disabled. I have attached two png's one of the device manager showing the settings and the other the power options. I'm not sure if there would be another location on the computer that may work for that, but if there is I can definitely check on it.
04-08-2013 10:18 AM - edited 04-08-2013 10:19 AM
I think I may have found a solution. I ran my test twice without any problems. I decided to use an externally powered USB hub on the computer in question. The program was also using 2 other USB connections in addition to the one Xitron. So now I have tested the program twice with about 30 minutes of sampling data each. It could be the computer's USB hub wasn't able to provide enough consistent power for the USB to serial connection to work; but I think this problem is fixed at this time.