ActiveX Performance Issue (Urgent Request)

[Dan Bookwalter]

We have an issue here where I dont have all the info but am hoping that maybe someone has some idea what might be going on , we have an ActiveX control that is written by a third party vendor who doesnt know LabVIEW. This driver uses mouse calls to talk to 24 USB devices , the issue is that when it is used in VB or VBA in Excel it works fine and is very fast , but , in LV it works but takes very long to return , longer than 300ms per USB device , so as you add more devices it gets slower and slower and slower.... We put the VI into the DAQ thread and it made no difference , if you put it in the User Interface thread it runs very fast , but , it doesnt always return the proper values..... any ideas ?? the vendor is not being cooperative :-( the developer has spent over two months on the LabVIEW program so changing languages is not an option....

Thanks

Dan

p.s. sorry for the limited info , but , it is about all i have to go on at the moment...

[Tim_S]

QUOTE (Dan Bookwalter @ May 22 2008, 09:07 AM)

We have an issue here where I dont have all the info but am hoping that maybe someone has some idea what might be going on , we have an ActiveX control that is written by a third party vendor who doesnt know LabVIEW. This driver uses mouse calls to talk to 24 USB devices , the issue is that when it is used in VB or VBA in Excel it works fine and is very fast , but , in LV it works but takes very long to return , longer than 300ms per USB device , so as you add more devices it gets slower and slower and slower.... We put the VI into the DAQ thread and it made no difference , if you put it in the User Interface thread it runs very fast , but , it doesnt always return the proper values..... any ideas ?? the vendor is not being cooperative :-( the developer has spent over two months on the LabVIEW program so changing languages is not an option....

From what you've posted, I believe your best bet is to simplify your application to one VI (if possible) and then contact National Instruments technical support if you're still having issues.

Tim

[alukindo]

Dan:

How are you capturing events for the ActiveX control? I am assuming that you may need to capture mouse events and others.

ActiveX controls can be registered to capture their native events via LabVIEW ActiveX Events call back function node. Some times this method works better than capturing the events using LabVIEW polling or by using LabVIEW's own event structure.

Attached is an Example node where ActiveX native events are captured via a LabVIEW call-back function node. This is for an ActiveX grid that I use with LabVIEW.

Anthony

[alukindo]

Dan:

The other question is whether the driver file is delivered as an ActiveX *.OCX file or and ActiveX *.dll file? These behave and need to be treated quite differently.

Anthony