LabVIEW
Labview/LabWindow Driver
Hello All,
I got some basic question want to ask you all,
1. In general, we will implement a .VLL Library file with a group of VI set to control hardward,
If I got a normaal DLL file, (Miscrosoft/Borland format), What should I do to modify it for support Labview.?
What is the necessary steps? any illustration example on site?
2. What is the difference for writing a Labview Driver and Labwindow Driver individually?
3. What is the relationship among .vi, .fp and .sub ?
much thanks ,
@nonomiya wrote:
Hello All,
I got some basic question want to ask you all,
1. In general, we will implement a .VLL Library file with a group of VI set to control hardward,
If I got a normaal DLL file, (Miscrosoft/Borland format), What should I do to modify it for support Labview.?
What is the necessary steps? any illustration example on site?
2. What is the difference for writing a Labview Driver and Labwindow Driver individually?
3. What is the relationship among .vi, .fp and .sub ?
much thanks ,
1. I guess you mean LLBs here, not sure what a VLL would be. If you can go with the LabVIEW native interfaces such as VISA, GPIB, TCP/IP and such interfaces this is almost always the best. No need to do DLLs then.
Normal DLLs can be interfaced through the Call Library Node. It is however a problem to create complex data types to pass to DLLs so you would be good advised to make sure the parameter list of functions takes simple data only such as skalars, arrays and strings, but refrains from using complex structures.
2. A LabVIEW driver typically will be written with LabVIEW icons and sometimes calls to DLLs through the Call Library Node and a LabWindows driver will be obviously C code and an fp file for the function panels of the driver functions.
3. A .vi is the file that holds the LabVIEW frontpanel, blockdiagram and compiled code of a LabVIEW programming function. The fp file is the file containing the function panels you use in LabWindows CVI when interactively invoking a library function. There used to be a feature built into LabVIEW to convert an FP file and its associated DLL into a VI library but that only creates a VI for each function panel in the fp file and creates code on the diagram to call the appropriate function in the DLL. Nice for being able to say you have a LabVIEW driver available, but for most LabVIEW developers rather useless as they want to see the diagram code and be able to debug into the code. This converter has been taken out from the latest LabVIEW version and you can download a separate standalone utility somewhere from the NI site instead.
Rolf Kalbermatter
