Saving VME data...

[Sasha]

I am using Labview 6i to control and hopefully save data from a 32 channel QDC on a VME crate. I am able to read from the device but I am unable to successfully save any data from this action. The VME Read function/VI is placed in a True/False window, and I am attempting to use the save-to-spreadsheet VI outside of the loop - but I only receive the default constant placed in the False loop...Any reason why I cannot save the data being read from the VME bus? I can even view the data being read on screen, such as a data acknowledged hex number, but no solution which can save this data. The number being displayed is an unsigned 32 bit integer. Is there a standard process for VME data acquisition using a VME-PCI card for Labview? Any help would be greatly app
reciated.

[Josh_KNH]

Hello Sasha,

If you are successfully reading data from your VME device, then there should not be a problem with saving it to a spreadsheet file.

A couple of suggestions I can offer to you are as follows:

1. If you are reading back some data, but it is from the False case of your case statement, you should be checking to see what occurs before that case statement and is actually forcing the False case statement to execute before the True case.
2. You should verify that data is being read back correctly and that a read or write to the VME device is not actually returning an error. Use a probe to check this scenario.

Where did you get the VI for the device you are trying to communicate with? If there are no actual errors occurring, but no data is being returned
, that typically suggests an issue with the programming, so it might help to start your troubleshooting there. There is not a default way to perform data acquisition from a VME device, because every VME device manufacturer has the liberty to program their device in a unique manner, so long as it complies with the VME specification.

Also, the use of probes and other troubleshooting techniques in LabVIEW can help narrow down this issue. You can find more information on these debugging techniques in Chapter 6 of the LabVIEW User Manual, linked below. Please let us know if we can assist further.

LabVIEW User Manual

Josh Hernstrom
Applications Engineering
National Instruments