agilent 54622d instrument driver problem

[Nomidaiganes]

Hello!

I'm using agilent 54622d oscilloscope to gather data. I need to record signals with length of 10us. The instrument driver's signal length minimal value is 50us. This seems a bit odd because the scope is capable of recording much smaller lengths of signals but the labview instrument driver is not. Is this really possible or have I misunderstood something? I added the pictures of the front panel and the block diagram. Any ideas?

Thanks,

Jürgen

[Dennis_Knutson]

The help for the Configure Acquisition Record subVI states 50ns is the minimum. Probably just a typo in the help in the main VI. There is no enforcement of any value in the driver. Have you entered a timebase value that you wanted and gotten any error from the scope?

p.s. You really don't want to do all of that code in a loop. You should do all of the initialization only once. Move that and the close to outside the loop.

[Nomidaiganes]

When I manually enter smaller values I get an error saying that the value is out of range. I attatched an image of the context help window, anything out of the given range gives an error. Any more ideas?

[Dennis_Knutson]

Attaching an image of the help window does not do any good. I can open that myself and as I said, the help for the subVI says something different. Show the error. If you are getting an error from the scope, the issue is with the instrument and not the driver.

[Nomidaiganes]

Hello again!

As I was trying to run the VI again I ran into a new problem. LabVIEW gives a new error:

The weird part is that the VI worked, the problem lied in the range. While waiting for your replay I explored some other ways to capture data and installed the Intuilink software. Besides that nothing else has changed. The error is the same even if I deliberately choose a wrong option from the VISA session drop down list, for example LPT. Then again if I run the initialise.VI from the instrument driver pack it gives the correct VISA Resource Name Out and no error out, so that seems to work.

Any suggestions, please?

[Nomidaiganes]

Okey, i got my Vi rnning again, reinstalling the instrument driver did the job.

Going back to the previuos problem, the out of range eroor is as follows:

Could you please explain why is this happening?

[Tanya_V]

Hi Nomidaiganes,

Have you been able to run this example at all with the default values?

If so, are you changing more than one value when you get the error? The error message is fairly non-specific.

[Nomidaiganes]

The Vi runs just fine with all the default values. It gives the out of range error when i change the record lenght to something outside the given range. So if I understand correctly you cannot see any reason why this range is limited to these values? (50.00E-6 - 500.0)

Regards,

Nomidaiganes

[Tanya_V]

Hi Nomidaiganes,

There are two values that control acquisition rate: Time per Record, and Min Record Length. I don't have the device manual, but if you check in the manual, it should explain how those values are used. The limitation likely has something to do with the maximum acquisition rate.

Otherwise, could you not acquire 50us of data and then just truncate it to 10us?

Have a great day!

[Nomidaiganes]

Hello again!

It seems I have to accept the capabilities of the VI. But I ran into another problem. The VI works fine with GPIB but not with serial connection. I have tried different baud rates and handshakes it still gives me the same error:

 VISA:  (Hex 0xBFFF001E) The specified state of the attribute is not valid, or is not supported as defined by the resource.

Gathering data with excel works fine over RS-232. So the COM port itself cannot be the problem. If the excel window is kept open and I try to run the VI again, it gives the following error: VISA:  (Hex 0xBFFF0072) The resource is valid, but VISA cannot currently access it. As muc as I understand this is caused by the fact that the com port is already in use. I hope this description is helpful.

Could anyone please suggest why this is happening?