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    Process Trend ActiveX Control

     Developers Guide 
    This section of the document describes the programmatic interface to the Process Trend OCX. It assumes that the reader is familiar with VB Script, and has a general knowledge of Microsoft's ActiveX (COM) technology.

     

    Properties

    NumTags

    The number of tags to be trended, as an integer from 1 to 4.
    Type:Long
    Default:1
    Maximum:4
    Minimum:1

    PhdHostName

    The name of the PHD Host.
    Default:PHD
    Type:String

    PhdMinConfidence

    The minimum acceptable PHD confidence for historical data.
    Type:Long
    Default:100
    Maximum:100
    Minimum:0

    PhdSampleMethod

    The sample method to use, either SNAPSHOT or AVERAGE.
    Default:SNAPSHOT
    Type:String

    PhdUserName

    The user name for logging on to the PHD Host.
    Default:PHD_READONLY
    Type:String

    PhdPassword

    The user's password for logging on to the PHD Host.
    Default:PHD_READONLY
    Type:String

    MaxPhdSamples

    The maximum number of samples that will be fetched in a call to the Visual PHD DLL. The actual number of samples requested will depend on the history type and the duration over which historical data is required.
    Type:Long
    Default:250
    Maximum:500
    Minimum:6

    HistoryWindow

    The history window is the duration of history that is displayed, expressed as a string. For example, 30 minutes is expressed as "30m". The history windows are defined in the file ProcessTrend.XML.
    Default:30m
    Type:String
    Valid Entries:As defined in ProcessTrend.XML

    IsRealTime

    Read only property indicating whether the graph is displaying real-time or historical data.
    Note:Read Only
    Type:Boolean

    IsZoomed

    Read only property indicating whether the graph is zoomed-in.
    Note:Read Only
    Type:Boolean

    StartTime

    Read only property indicating the start time of the currently displayed data.
    Note:Read Only
    Type:Date

    EndTime

    Read only property indicating the end time of the currently displayed data.
    Note:Read Only
    Type:Date

    TagParameter(Index as Long)

    The tag name and parameter of the given trace. The trace number (1 to 4) is specified by the Index parameter.
    Note: The tag name and parameter must be specified as it is defined in PHD - so be careful if the LCN and PHD tag names are different
    Type:String
    Index:1 to 4

    PtDesc(Index as Long)

    The point descriptor for the given trace.
    Note:Only the first 24 characters of the string are currently displayed, although it is planned that future releases of the OCX may be able to display longer strings
    Type:String
    Index:1 to 4

    EuDesc(Index as Long)

    The engineering units descriptor for the given trace.
    Note:Only the first 8 characters of the string are currently displayed
    Type:String
    Index:1 to 4

    NumDecimals(Index as Long)

    The number of digits shown after the decimal point for the given trace. This formatting applies for the numbering on the Y axes, the EUHI and EULO boxes, and for the tool tip.
    Type:Long
    Index:1 to 4
    Maximum:4
    Minimum:0

    PVEUHI(Index as Long)

    Engineering units high value.
    Note:Must be greater than the PVEULO
    Type:Single
    Index:1 to 4

    PVEULO(Index as Long)

    Engineering units low value.
    Note:Must be less than the PVEUHI
    Type:Single
    Index:1 to 4

    Simulate

    Specifies whether the OCX should connect to the Visual PHD Simulator instead of to PHD.
    Type:Boolean
    Default:False

    BackColour

    This is the background colour for the control, not for the graph itself.
    Type:OLE_COLOR
    Default:Grey (0xD4D0C8)

    GraphBackColour

    This is the background colour for the graph itself.
    Type:OLE_COLOR
    Default:Black (0x000000)