lakeshore error at initialize

[vob555]

I am controlling the Lakeshore 340 through GPIB with the instrument drivers. It works most of the time, but sometimes i get:

Error -1074003951 occurred at LSCI 340 Initialize
Possible reason(s):
LabVIEW: (Hex 0xBFFC0011) Identification query failed.

Does anybody know any possible reasons why this is happening? Thanks.

[vob555]

I forgot to mention that I running LabView 7.1 on Mac OSX 10.3.9
Thanks.

[Chris_R.]

Hello!

That error usually occurs when your instrument does not respond to the identification command.  Most of our software will automatically send this command, so if your instrument does not support it, it may throw this or a similar error (timeout, etc).  Sometimes you will need to turn your instrument off and back on again after it is sent this command.  Instruments will often lock if they are sent a bad command, so you may need to reset it.  This link (http://www.ni.com/support/labview/visa/verr1.htm) talks about one way that is known to correct the error you are getting.  I found it by searching for "1074003951" at www.ni.com.  I am not sure why your instrument works most of the time, but sometimes you get this error.  This may be happening if there is no wait between your port configuration and your write or between your write and your read.  Is this error showing up at the beginning of your program or somewhere after it starts?  Are you sending the identification command intentionally or is it automatically sent?  If you are still having trouble, please send me this information and I will look into it further.  I hope this information helps you fix this problem, but let me know if you have any additional questions.  Have a great day!

Chris R.

Applications Engineer

National Instruments

[vob555]

Thanks.  I think i figured out what was happening.  My main program loop updates any setting changes to the instrument among other things.  I also have a separate independent while loop that querys the instrument's heater output a few times a second.  I believe that the timing of these loops was such that sometimes they would collide and one loop would try to talk to the instrument while the other loop was already talking to it, thus producing the initialize error.

[Chris_R.]

That's great that you seem to have found the problem.  That does seem like those loops would cause that problem.  If you run into any more trouble, just let us know and we will be happy to help you further.  Best of luck to you and have a great day!

Chris R.

Applications Engineer

National Instruments