Overview of the OPC Classic HDA Collector

The OPC Classic Historical Data Access (HDA) collector collects data from any OPC HDA 1.2 - compliant OPC server (such as CIMPLICITY). The collector automatically determines the capability of the OPC server to which it is connected and supports the appropriate features based on this information.

Topology:

The OPC Classic HDA collector and the OPC Classic HDA server support remote connectivity. If the OPC Classic HDA server and the OPC Classic HDA collector are on different machines, ensure that:
  • The DCOM setting is provided for both the server and collector machines.
  • Before starting the collector, ensure that NT AUTHORITY/SYSTEM has SysAdmin privileges.
Features:
  • You can browse the source for tags and their attributes on an OPC server that supports browsing.
  • Only unsolicited data collection is supported; when changes to the OPC source tags are detected, they are sent to the Historian server. The minimum poll interval is 100ms. The collector duplicates raw samples from the OPC server into the Historian data archive.
    For unsolicited data collection, if collector compression is disabled, all new values produce an exception. And, the deadband percentage is determined by the collector deadband percent. You can only configure the collector deadband percent by enabling compression.
    Note: You must set the Time Assigned by field to Source if you have unsolicited tags getting data from an OPC Classic HDA collector.
  • The supported timestamp resolution is 1ms.
  • Floating point, integer, binary, and string data are supported.
  • Device timestamps are accepted.
Supported data types:
The OPC Data Type Recommended Data Type in Historian
I1- 16 bit signed integer Single Integer
I4- 32 bit signed integer Double Integer
R8- 64 bit double float Single Float
UI2- 16 bit unsigned single integer Double Float
UI4- 32 bit unsigned double integer Unsigned Integer
UI8- 64 bit unsigned quad integer Unsigned Double Integer
I8- 64 bit quad integer Quad Integer
BSTR Variable Sting
BOOL Boolean
I1- 8 bit single integer Byte
Note: The OPC Classic HDA collector requests data from the OPC Classic HDA server in the native data type. The OPC Classic HDA collector then converts the received value to a Historian Data Type before sending it to the data archiver.
Supported tag attributes:
  • Tagname
  • Source Address
  • Engineering Unit Description
  • Data Type
  • Hi Engineering Units
  • Lo Engineering Units
  • Is Array Tag
The Engineering Unit Description, Hi Engineering Units and Lo Engineering Units vary based on the OPC server vendor.
Note: While some of these attributes are queried on a browse, they are not shown in the browse interface. These attributes are used when adding a tag, but it is not visible to you if all attributes come from the server or not.