Data plugins

[BLV]

I am working on a plugin that reads RDF data. Is there a way of getting the maximum and minimum values of a data channel inside the plugin? I am unable to get anything if I use the "Maximum" and "Minimum" standard channel properties. In the absence of this, I have to scan through all the channel values in order to check for Data system Exceed of the raw data(before application of factor and offset).

Thanks in advance.

[Brad_Turpin]

Hi BLV,

There is nothing in the VBScript DataPlugin functions to calculate maximum or minimum values of a DirectAccessChannel.  Sometimes you get lucky and the file format has that information (or the scaling information) listed as properties in the file header section.  Other times you get lucky and don't need to know the extrema of the channels withing the DataPlugin.  You do have the option of creating a custom load event in DIAdem to calculate the extrema and apply the scaling factors, and this can be integrated into DIAdem so that a user never knows that when they drag an RDF file into DIAdem the raw parsing is handled in the DataPlugin but the extrema calculation and scaling are happening during the load process in DIAdem.

Another option to consider is to create your DataPlugin with LabVIEW instead of VBScript.  It means you end up with an installer more like 30MB - 90MB in size, but the advantage is that you then have all the functions in LabVIEW inside the DataPlugin, and there is certainly and array min/max function in LabVIEW you could use.  The LabVIEW DataPlugin API is listed for download at www.ni.com/dataplugins if you're interested.

Where do these RDF data files come from?  Perhaps there is already a DataPlugin for them.  That extension sounds familiar to me.

Brad Turpin

DIAdem Product Support Engineer
National Instruments