Capabilities of the OPCUA DA Collector

The following table outlines the capabilities of the Historian OPCUA DA Collector.

Browse Source For TagsYes (on OPCUA servers that support browsing)
Browse Source For Tag AttributesYes
Polled CollectionYes
Minimum Poll Interval100 ms
Unsolicited Collection

Yes. If you are using an OPCUA DA collector with unsolicited data collection and the collector compression is disabled, new values must produce an exception. When the OPCUA DA collector performs unsolicited collection, the deadband percentage is determined by the collector deadband percent. You can only configure the collector deadband percent by enabling compression.

Timestamp Resolution100ms
Accept Device TimestampsYes
Floating Point DataYes
Integer DataYes
String DataYes
Binary DataYes
Python Expression TagsNo
Note: You must set Time Assigned by field to Source if you have unsolicited tags getting data from an Historian OPCUA DA Collector.

Tag Attributes Available on Browse

The following table outlines the tag attributes available when browsing.

Tag nameYes
Source AddressYes
Engineering Unit DescriptionYes, varies by OPCUA Server Vendor.
Data TypeYes. See Selecting Data Types.
Hi Engineering UnitsYes, varies by OPCUA Server Vendor.
Lo Engineering UnitsYes, varies by OPCUA Server Vendor.
Hi ScaleYes
Lo ScaleYes
Is Array TagNo
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 you will not be able to see whether or not all attributes come from the server.

Selecting Data Types

The following table lists the data types recommended for use with Historian.

OPCUA Data TypeRecommended Data Type in Historian
I1 - 16 bit signed integerSingle Integer
I4 - 32 bit signed integerDouble Integer
R4 - 32 bit floatSingle Float
R8 - 64 bit double floatDouble Float
UI2 - 16 bit unsigned single integerUnsigned Single Integer
UI4 - 32 bit unsigned double integerUnsigned Double Integer
UI8 - 64 bit unsigned quad integerUnsigned Quad Integer
I8 - 64 bit quad integerQuad Integer
BSTRVariable String
I1 - 8 bit single integerByte
Note: The Historian OPCUA Collector requests data from the OPCUA DA server in the native data type. Then the Historian OPCUA DA collector converts the received value to a Historian Data Type before sending it to the Historian database.

OPCUA Group Creation

To increase performance, it is recommended that you limit the number of OPCUA groups created by the Historian system. To do this, consider grouping Historian tags (collected by the Historian OPCUA DA Collector) using the least amount of collection intervals possible.