OPCHDAAttributes coding group

This code group contains the attribute IDs specified in the OPC Historical Data Access Specification, Version 1.20, Released December 10, 2003.

Lua access code

To access the code of the codings below, append the coding group name and coding name to inmation.model.codes, see an example below.

return inmation.model.codes.OPCHDAAttributes.OPCHDA_ARCHIVING

Codings

Name Code Description
OPCHDA_ARCHIVING 5 Indicates whether historian is recording data for this item (0 means no)
OPCHDA_DATA_TYPE 1 Specifies the data type for the item. See the definition of a VARIANT for valid values (VT_R4, etc.)
OPCHDA_DERIVE_EQUATION 6 Specifies the equation to be used by a derived item to calculate its value. This is a free-form string
OPCHDA_DESCRIPTION 2 Describes the item
OPCHDA_ENG_UNITS 3 Specifies the label to use in displays to define the units for the item (e.g., kg/sec)
OPCHDA_EXCEPTION_DEV 16 Specifies the minimum amount that the data for the item must change in order for the change to be reported to the history database
OPCHDA_EXCEPTION_DEV_TYPE 17 Specifies whether the OPCHDA_EXCEPTION_DEV is given as an absolute value, percent of span, or percent of value
OPCHDA_HIGH_ENTRY_LIMIT 18 Specifies the highest valid value for the item. A value for the item that is above OPCHDA_HIGH_ENTRY_LIMIT cannot be entered into history. This is the top of the span
OPCHDA_ITEMID 13 Specifies the item id. This is used to allow filtering in the CreateBrowse method, therefore the intention is to return only the leaf portion of an ItemID, not the fully qualified ItemID which would be returned from a GetItemID call
OPCHDA_LOW_ENTRY_LIMIT 19 Specifies the lowest valid value for the item. A value for the item that is below OPCHDA_LOW_ENTRY_LIMIT cannot be entered into history. This is the zero for the span
OPCHDA_MAX_TIME_INT 14 Specifies the maximum interval between data points in the history repository regardless of their value change
OPCHDA_MIN_TIME_INT 15 Specifies the minimum interval between data points in the history repository regardless of their value change
OPCHDA_NODE_NAME 7 Specifies the machine which is the source for the item. This is intended to be the broadest category for defining sources. For an OPC Data Access Server source, this is the nodename or IP address of the server
OPCHDA_NORMAL_MAXIMUM 11 Specifies the upper limit for the normal value range for the item. OPCHDA_NORMAL_MAXIMUM is used for trend display default scaling and exception deviation limit calculations
OPCHDA_NORMAL_MINIMUM 12 Specifies the lower limit for the normal value range for the item. OPCHDA_ NORMAL _MINIMUM is used for trend display default scaling and exception deviation limit calculations
OPCHDA_PROCESS_NAME 8 Specifies the process which is the source for the item. This is intended to the second-broadest category for defining sources. For an OPC DA server, this would be the registered server name
OPCHDA_SOURCE_NAME 9 Specifies the name of the item on the source. For an OPC DA server, this is the ItemID. For non-OPC sources, the meaning of this field is server-specific
OPCHDA_SOURCE_TYPE 10 Specifies what sort of source produces the data for the item. For an OPC DA server, this would be "OPC". For non-OPC sources, the meaning of this field is server-specific
OPCHDA_STEPPED 4 Specifies whether data from the history repository should be displayed as interpolated (sloped lines between points) or stepped (vertically-connected horizontal lines between points) data. Value of 0 indicates interpolated