Overview of the OPC Classic DA Collector

The OPC Classic Data Access (DA) collector collects data from any OPC 1.0 or OPC 2.0 compliant OPC server (such as CIMPLICITY). The collector automatically determines the capability of the OPC server to which it is connected and supports appropriate features based on this information.

Features:
  • You can browse the source for tags and their attributes on an OPC server that supports browsing.
  • Both the polled and unsolicited data collection are supported; when changes to the OPC source tags are detected, they are sent to the Historian server. Unsolicited data collection is supported for OPC 2.0 only. 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.

  • The supported timestamp resolution is 1ms.
  • Floating point, integer, binary, and string data are supported.
  • Python expression tags 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
R4 - 32 bit float Single Float
R8 - 64 bit double float Double Float
UI2 - 16 bit unsigned single integer Unsigned Single Integer
UI4 - 32 bit unsigned double integer Unsigned Double Integer
UI8 - 64 bit unsigned quad integer Unsigned Quad Integer
I8 - 64 bit quad integer Quad Integer
BSTR Variable String
BOOL Boolean
I1 - 8 bit single integer Byte
Note: The collector requests data from the OPC server in the native data type. Then the collector 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.