Need help using I/O assistant.

[Thomasp]

Hello all,

I just started to use Labview and I have a question. I tried searching for it but I can't seem to find the answer.

I connected my TDS 784D oscillopscope as a GPIB device and all I'm trying to do is display the waveform from the oscillopscope. I want to use the I/O assistant. Can anybody tell me what I should do please? I usually get a timeout error when I tried to "read and parse".

If this question has been answered already, please point me in the right place. Thank you in advance.

Message Edited by Thomasp on 07-18-2005 02:48 PM

[Dennis_Knutson]

First, I would recomend that you use a driver for the scope instead of the I/O Assistant. There are both native LabVIEW and IVI drivers available for it. Unless you need the interchangeability of IVI, go with the LabVIEW driver. Pick the one you want at http://sine.ni.com/apps/we/niid_web_display.drv_results?p_app_area=&p_man=tektronix&p_keywords=784&p...

If you still want to use the I/O Assistant, you have to first setup the scope using the correct commands. What is the command that you write before doing the read and query? If the commands are not correct to initiate a data transfer, there will be nothing to read.

[Thomasp]

I tried to use the IVI drivers for it but there were several errors that I could not figure out. I really want to learn how to use the I/O assistant. I'm not really sure which command to write if I only want to display the waveform from the oscilloscope. I do not know how to initiate a data transfer. I'm very new at this. Please any help is greatly appreciated.

[Dennis_Knutson]

In order to use the I/O Assistant, you have to study the instrument's programming manual and understand all of the commands required to initialize the instrument for a measurement (vertical/horizontal setting, trigger, etc), then the commands to transfer a waveform, and then know the format of the waveform transferred (i.e. binary, floating point, header, etc.). If you have questions on the command syntax, you might want to ask Tektronix about that.

The errors you got from the IVI driver may have been because you didn't install the IVI Frameworks or the driver DLL. On the other hand, since you're trying to use the I/O Assistant, it doesn't sound like you need the abilities of IVI and the native LabVIEW driver would work better. If you use this, you won't have to understand the instrument programming details like you would with using the assistant and you'd have a lot more flexibility. You could though, look at the commands in the driver to see what is being sent to the instrument. Imho, though, you'd be reinventing the wheel.