Initiate waveform aquisition from Oscilloscope

[Gareth R]

Hi,

I am reasonably new to labview and i am currently trying to create a VI that will read my waveform from my oscilloscope (Lecroy waverunner LT372). I have been successful in doing this and now i want to adapt this to work with the math channel on the oscilloscope so that when the averaged waveform produced on the math channel after 1000 sweeps is sent to the front panel of the VI. What i would like to do is get the oscilloscope to initiate the VI after the 1000 sweeps has taken place to record the final averaged waveform. Is this possible and if so could anyone help me in trying to get this is work?

Alternatively if this is not possible, is it possible to get the VI to initiate the oscilloscope to start the 1000 sweeps on the math channel and not fetch the waveform from the oscilloscope until the 1000 sweeps have finished?

Thanks,

Gareth R

[JamesC]

Hi Gareth,

I have never used a LeCroy scope, but I have downloaded the instrument driver for your instrument from here.

I would use the Math functions found on the configuration pallette to do what you need as that way you don't have to know all the low level command to send the instrument.

You would have to use this method "get the VI to initiate the oscilloscope to start the 1000 sweeps on the math channel and not fetch the waveform from the oscilloscope until the 1000 sweeps have finished" to do what you want, as I do not know of a way to get the instrument to start the VI.

Hope this is helpful
Regards
JamesC
NIUK and Ireland

[alanjb]

Hi Gareth,

Alan from LeCroy Tech Support here...

There is a register you can poll to determine if the averaging is complete. It's the INR register.  It's a "change" register, meaning that it tells you what's changes since you last read it with the INR? query... There are bits in this register for "Waveform Processing has terminated in Trace n" (n = A, B, C or D)

Which driver are you using?  And are you using summed or continuous averaging?

For summed averaging on Trace A, you can put the scope into NORMAL trigger mode, and then send the query INR? and read the result... Parse the result to get the numeric value, and then AND it with 256 to determine if processing is complete on trace A. (Trace B would be 512, etc).   Do this in a loop until you find that the AND is true.

To send the INR? query and to read the result, use the low-level Instrument Write and Instrument Read VI's that are in your driver. I also recommend using LeCroy's free application Scope Explorer to come up the learning curve... With this application, you can type INR? into a terminal window and immediately see the result. No programming required...

Feel free to give me a call at 800-553-2769 if you have any questions.

Best Regards,
Alan Blankman

[alanjb]

I meant to add the following link, which is to the WaveRunner Remote Control manual. Check out page 147 (154 of the PDF file) for the definition of the INR? register.

http://www.lecroy.com/tm/library/manuals/WaveRunnerSeries/RemoteControlManual/WR2_RCM_RevB.pdf

--Alan