lecroy lcwave communication problem with offset

[JimmyP23]

Greetings,  I've downloaded the lcwave library and updated all visa and ivi drivers in order to communicate via TCP/IP with a lecroy wavesurfer 44Xs.  For a few days I had successful communication with the scope and was able to tranfer waveforms using lcwave Acquire Multiple Waveforms.vi.  Then all of a sudden (aka, I must've accidentally changed something in a subvi somewhere) the waveforms I obtain off the scope are inversely offset.  i.e. a +2.5 V vertical offset on the scope results in all of my data being offset by -2.5 V on the vi. 

I occasionally recieve the age old 'Error 85 occured at Scan From String (arg 1) in lcwave Wait for Acquisition Complete.vi->lcwave Acquire Multiple Waveforms.vi' that I've seen on some of these boards, but none of their respective fixes have helped.

I must admit that originally I got rid of the '*CLS;' in steps 0 and 1 in lcwave Initialize.vi to prevent the scope from resetting every time I ran the vi, and it worked fine for days.  However, I restored these commands in an effort to troubleshoot.  I also 'reextracted' lcwave to instr.lib to hopefully get rid of whatever changes I had made, but it made no difference.

I am running Labview 7.1.  Any help is appreciated.

Thanks,

Jim

[NathanT]

Hello Jim,
       I don't believe that IDNet has an IVI driver for your scopes, so you don't need to worry about the IVI Compliance Package being up to date.  It is good that everything was working for a couple of days.  It sounds like either the encoding of the waveform or formatting of the offset command might have changed.  The easiest step to take is completely delete the lcwave folder from your LabVIEW instr.lib folder.  After that is done, make sure LabVIEW is closed and then place a new fresh copy of the driver in the instr.lib folder and start LabVIEW.  Try running one of the examples and see if it works correctly.  If so, make a simple application that applies an offset to the waveform and test that.  If that works, try running your application.

Let us know how it goes,

NathanT

[MXI Master]

Message Edited by MXI Master on 06-03-2008 10:28 AM

[alanjb]

Hi Jim,

Alan from LeCroy Tech Support here...

I agree wholeheartedly with deleting the existing lcwave folder and then re-installing it.  This is an excellent first step. You may have indeed created the problem when changing the driver.

Regarding *CLS...  This command doesn't reset the scope; it simply clears some registers.  The Initialize VI contains a call to perform a reset;  to avoid resetting the scope, simply wire a False to the Reset terminal of the Initialize VI.

Regarding the Scan From String error... I've never seen Wait for Acquisition Complete generate this error, but I've seen it elswhere.  Make sure that you begin your program by calling Initialize; this can prevent this kind of problem from occurring

If the above changes don't fix the problem, then please email me a screenshot of what you are seeing in your VI as well as a screenshot from the scope.  Here's an FAQ on how to save a screenshot on the scope, in case you haven't done this yet: http://www.lecroy.com/knowledgebase/scopes/details.asp?menuid=6&id=449

By the way, I'm working on the next rev of the driver, and plan on submitting it to NI sometime this month.

Best Regards,

Alan

[JimmyP23]

Alan and Nathan,

Thank you for your suggestions.  They've helped and all waveform acquisition vi's are working now.  It took a combination of deleting & reinstalling lcwave (apparently just re-extracting/overwriting as I was doing before wasn't enough, although I can't imagine why), and using lcwave initialize.vi instead of lcwave initiate.vi.  Additionally, setting the reset to false as the default value helped.  You've mentioned on other threads to reboot often throughout the troubleshooting process.  I can't recommend this enough.

Thank you again,

Jim

[alanjb]

Hi Jim,

Glad to hear that the problem is solved!  Let me know if you have any additional questions, or if the driver needs some enhancements for a future revision.

Best Regards,
Alan