OPC Classic HDA Server

About OPC Classic HDA

About OPC Classic Historical Data Access (HDA)

OPC Classic HDA is widespread standard, which provides specifications to retrieve and analyze historical process data. This data is typically stored in a process data archive, database, or a remote terminal unit (RTU). You can analyze this data for trending, fault prediction, performance assessment, and so on.

Advantages of Using OPC Classic HDA

With OPC Classic HDA, the exchange of historical data between an application and any data archive is consistent. Therefore, OPC HDA client applications that implement trends, reports, or spreadsheets can retrieve historical process data from Historian and other OPC Classic HDA servers.
The OPC Classic HDA specifications are based on Microsoft's Object Linking and Embedding (OLE) and Distributed Component Object Model (DCOM) technologies. Therefore, OPC is endorsed by Microsoft.
You can configure DCOM client and server software programs to run on the same computer node or distributed across a network of computers.
The OPC Classic HDA is created to allow various automation applications to communicate with one another based on the historical data, regardless of the manufacturer. This allows greater flexibility and reliability when setting up automation systems.
The OPC Classic HDA server specification provides a common view of automation information managed by the system for which the server was written.
Developing OPC Classic-compliant applications is simplified because only one I/O interface is required.
Using OPC-compliant applications increases the flexibility of your automation processes because they can also communicate with devices other than those specified by the applications' developers.
Multiple OPC Classic HDA compliant client applications can communicate with an OPC Classic HDA server simultaneously.

For more information on OPC Classic HDA, visit the OPC Foundation's website.

Data Flow

The following diagram shows the data flow between the OPC Classic HDA clients, the OPC Classic HDA server, and Proficy Historian.

About the Historian OPC Classic HDA Server

The Historian OPC Classic HDA server retrieves historical process data from Proficy Historian, and sends it to OPC Classic HDA clients. It dynamically updates the clients when tags are added and/or deleted in Historian. Clients that comply with this specification can connect to the OPC Classic HDA server to retrieve data from Historian.

Features of the OPC Classic HDA Server

The server complies with the OPC HDA Server specification 1.2.0.
You can browse for all the tags available in Historian.
You can convert Historian timestamps, data types, and qualities to OPC HDA timestamps, data types, and qualities, respectively.
You can automatically reconnect to the Historian server when connection is lost.
You can connect multiple instances of the OPC Classic HDA clients to the same server without any additional configuration. The OPC Classic HDA server has been tested with the following OPC Classic HDA clients:
- OPC Foundation HDA Sample client. You can download this client from www.opcfoundation.org
- Advosol HDA test client. You can download this client from http://www.advosol.com/t-free-tools.aspx

Limitations

The OPC Classic HDA server supports only synchronous read raw interface.

Set Up the Historian OPC Classic HDA Server

Before you begin

Install the HDA server and Historian Administrator. For instructions, refer to Install Client Tools.
Disconnect and reconnect all the OPC HDA clients.

Procedure

Access Historian Administrator.
Select Browse for Server, and select the Historian server that you want to connect with the OPC Classic HDA server.
Select Set Selected Server as Target of HDA Server, and then select OK.
The selected server is set as the target Historian server.
Configure any external OPC HDA clients to connect to the OPC Classic HDA server. You can connect multiple instances of the clients to a single server.
When an OPC HDA client tries to connect to the Historian OPC Classic HDA server, and if an instance of the server is not available, the instance is started, and the client connects to the running instance of the server. The Historian OPC Classic HDA server continues to run as long as there are clients connected to it.
Note: The OPC Classic HDA server uses Proficy.Historian.HDA as the program ID (ProgID).

What to do next

If you have installed the OPC Classic HDA server on a remote machine, enable the firewall.

Enable Tag-Level Security

Procedure

Access Registry, and go to the following path: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Intellution, Inc.\iHistorian\HDAServer
In the TargetHistorianServer registry key, enter details in following format: MachineName,UserName,Password,Timeout

Supported Attributes

The following table provides a list of the attributes supported by the OPC Classic HDA collector.


Historian Property Type	OPC Classic HDA collector Attributes	Data Type	Description
Data Type	OPCHDA_ DATA_TYPE	Int16	The data type for the item. For information, refer to Supported Data Types.
TagDescription	OPCHDA_ DESCRIPTION	String	The description of the item.
Engineering Units	OPCHDA_ ENG_UNITS	String	The units for the item (for example, kg/sec).
Archiving	OPCHDA_ ARCHIVING	Boolean	Indicates whether Historian stores data for this item. The following values are valid: 0: Indicates that data for this item is not stored. 1: Indicates that data for this item is stored.
ItemID	OPCHDA_ ITEMID	String	The Historian tag name. This is used to allow filtering in `CreateBrowsemethod`.

Supported Data Types

The following table provides a list of data types in Historian and the corresponding ones in the OPC Classic HDA server and the OPC UA HDA server.


Data Type in Proficy Historian	Data Type in the OPC Classic HDA server or the OPC UA HDA server.
Single Integer	VT_I2&endash; 16 bit signed integer
Double Integer	VT_I4- 32 bit signed integer
Quad Integer	VT_I8- 64 bit quad integer
Unsigned Single Integer	VT_UI2- 16 bit unsigned single integer
Unsigned Double Integer	VT_UI4- 32 bit unsigned single integer
Unsigned Quad Integer	VT_UI8- 62 bit quad integer
Byte	VT_I1
Boolean	VT_BOOL
SingleFloat	VT_R4- 32 bit float
Double Float	VT_R8- 64 bit double float
Variable String	VT_BSTR
Fixed String	VT_BSTR
Date	VT_DATE
Blob	VT_BSTR

Supported Quality Values

The following table provides a list of the quality values in Historian and the corresponding ones in the OPC Classic HDA server.


Proficy Historian Quality	OPC Classic HDA Quality	Description
ihOPCGood	OPC_ QUALITY_ GOOD	Indicates that there is no need for inspection. This quality is returned for the tags that have all the values archived properly.
ihOPCBad	OPC_ QUALITY_ BAD	Indicates a need for attention. This quality is returned for the tags that had problems during the collection.
ihOPCUncertain	OPC_ QUALITY_ UNCERTAIN	Indicates a need for inspection. This quality is returned when the data collection time is low and when there is no specific quality value.
ihOPCNA	OPC_ QUALITY_ BAD	Indicates a need for attention.

Supported Filter Attributes

The following table provides a list of attributes for which filtering is supported by the OPC Classic HDA server, and the corresponding ones in Historian, along with the supported operators for each.


Historian Property Type	OPC Classic HDA server Attributes	Supported Operators
Data Type	OPCHDA_DATA_TYPE	OPC_HDA_EQUAL_TO
Tag Description	OPCHDA_DESCRIPTION	OPC_HDA_EQUAL_TO
Engineering Units	OPCHDA_ENG_UNITS	OPC_HDA_EQUAL_TO
Item ID	OPCHDA_ITEMID	OPC_HDA_EQUAL_TO

Important: The OPC Classic HDA server filter strings are case-sensitive.

Although filtering is supported for the OPC_HDA_ARCHIVING attribute, do not use the filtering in the OPC Classic HDA clients because the value of this attribute is always true. Instead, you can refer to the log file to trace a history of communication events dealt with by the OPC Classic HDA server. You can also turn on the debug mode to more know more details in the log file. If an invalid filter is passed by an OPC HDA client, the OPC Classic HDA server returns all the available items in the address space.

Tip:

The wildcard character (*) will return all the tags.
The wildcard (key*) will return tags which begins with ???key???.
The wildcard (key) returns an exact tag name.

Turn On Debug Mode for Trace Log Files

About this task

The Trace Logging feature logs communications with the OPC Classic HDA server into an html file. Advanced users can use this log file to trace a history of communication events with the OPC Classic HDA collector server. It is designed for use by the support personnel only to assist in diagnosing issues with the Historian OPC Classic HDA server. By default, the log file is located in the following folder: C:\Proficy Historian Data\LogFiles.

The log file contains the following information:

The date and time when an event has occurred.
Errors and exceptions in parameters passed by an OPC HDA client.
The status of an OPC HDA client.

Procedure

Access Registry, and then access the following key folder:
- For Windows 32-bit: HKEY_LOCAL_MACHINECLASSES_ROOT\SOFTWARE\Intellution,inc\iHistorian\HDAServer\
- For Windows 64-bit: HKEY_LOCAL_ MACHINE\SOFTWARE\Wow6432Node\\Intellution, Inc.\iHistorian\HDAServer\
Modify values for DebugMode DWORD as follows, and then select OK:
1. In the Base box, select Decimal.
2. In the Value box, enter 255.

Results

The debug mode is turned on for the trace logs.

Example Trace Log File

The following message illustrates the type of information that the trace log file provides. In this message:

The black color indicates the status of events.
The blue color indicates the status of clients.
The red color indicates errors and exceptions passed by clients.

Browse Large Number of Collectors and Tags

About this task

In the OPC UA HDA server, the flat address space is used by default. This type of object model is used to browse a small number of tags. If you want to browse a large number of collectors and tags, enable the hierarchical address space.

Procedure

Access Registry, and then go to the following key folder: .
- For Windows (32-bit): HKEY_LOCAL_MACHINE\SOFTWARE\Intellution, Inc.\iHis- torian\HDAServer\
- For Windows (62-bit): HKEY_LOCAL_ MACHINE\SOFTWARE\Wow6432Node\\Intellution, Inc.\iHistorian\HDAServer\
Create a DWORD named HierarchicalAddressSpace.
In the Value box, enter 255.

Note: For a flat address space, this value is set to 0.
Select OK, and then close the Registry.
Restart the OPC Classic HDA server by disconnecting and reconnecting all the OPC HDA clients.

OPC Classic HDA Aggregates

In the OPC Classic HDA server, an aggregate is a function that is used to process raw data from an OPC Classic HDA server over a given range of time divided into discrete intervals. These aggregates can be further used to for various purposes, such as visualizing the trends in the data.

The standard aggregates supported are:

Minimum
Maximum
Average

The custom aggregates supported are:

Nearest
Before
After
GE Interpolative

Consider the following as a Historian Source for the Minimum, Maximum and Average Aggregates:


Timestamp	Value	Quality	Notes
Jan-01-2002 12:00:00	0	No Data	First archive entry Point Created
Jan-01-2002 12:00:10	10	Raw, Good
Jan-01-2002 12:00:20	20	Raw, Good
Jan-01-2002 12:00:30	30	Raw, Good
Jan-01-2002 12:00:40	40	Raw, Bad	Scan failed, Bad data entered
Jan-01-2002 12:00:50	50	Raw, Good
Jan-01-2002 12:01:00	60	Raw, Good
Jan-01-2002 12:01:10	70	Raw, Bad	Value is flagged as questionable
Jan-01-2002 12:01:20	80	Raw, Good
Jan-01-2002 12:01:30	90	Raw, Good
NULL	No Data	No more entries, awaiting next scan.

Consider the following Historian Source for Nearest, Before and After Aggregates:


Timestamp	Value	Quality	Notes
Feb-28-2002 12:01:30	987	Raw, Bad
Mar-01-2002 12:01:30	98765	Raw, Good
Mar-02-2002 12:01:30	9876	Raw, Bad
Jan-01-2002 12:00:00	0	No Data	First archive entry Point Created
Jan-01-2002 12:00:10	10	Raw, Good
Jan-01-2002 12:00:20	20	Raw, Good
Jan-01-2002 12:00:30	30	Raw, Good
Jan-01-2002 12:00:40	40	Raw, Bad	Scan failed, Bad data entered
Jan-01-2002 12:00:50	50	Raw, Good
Jan-01-2002 12:01:00	60	Raw, Good
Jan-01-2002 12:01:10	70	Raw, Bad	Value is flagged as questionable
Jan-01-2002 12:01:20	80	Raw, Good
Jan-01-2002 12:01:30	90	Raw, Good

Average Aggregate

The purpose of Average aggregation is to find the average value for a given time interval. It adds up the values of all good raw data in a specified time interval. The sum is then divided by the number of good values. Bad values are ignored in the computation.

If the user specifies a time range where no good data exists for an interval, the quality of the aggregate for that interval will be bad, OPCHDA_NODATA.

This aggregate returns the timestamp of the start of the interval.

Example 1

Start: Jan-01-2002 12:00:10 End: Jan-01-2002 12:00:20 Interval: 00:00:05


Timestamp	Value	Quality
Jan-01-2002 12:00:10	10	Calculated, Good
Jan-01-2002 12:00:15	0	No Data, Bad

Example 2

Start: Jan-01-2002 12:00:35 End: Jan-01-2002 12:01:00 Interval: 00:00:05


Timestamp	Value	Quality
Jan-01-2002 12:00:35	0	No Data, Bad
Jan-01-2002 12:00:40	0	Bad data in the interval
Jan-01-2002 12:00:45	0	No Data, Bad
Jan-01-2002 12:00:50	50	Calculated, Good
Jan-01-2002 12:00:55	0	No Data, Bad

Maximum Aggregate

The maximum actual time aggregate retrieves the maximum good raw value within the interval [s,e), and returns that value the timestamp of the aggregate will always be the start of the interval for every interval. If the same maximum exists at more than one timestamp, the oldest one is retrieved.

Example 1

Start: Jan-01-2002 12:00:10 End: Jan-01-2002 12:00:20 Interval: 00:00:05


Timestamp	Value	Quality
Jan-01-2002 12:00:10	10	Raw, Good
Jan-01-2002 12:00:15	0	No Data, Bad

Example 2

Start: Jan-01-2002 12:00:35 End: Jan-01-2002 12:01:00 Interval: 00:00:05


Timestamp	Value	Quality
Jan-01-02 12:00:35	0	No Data, Bad
Jan-01-02 12:00:40	0	No Data, Bad
Jan-01-02 12:00:45	0	No Data, Bad
Jan-01-02 12:00:50	50	Raw, Good
Jan-01-02 12:00:55	0	No Data, Bad

Minimum Aggregate

The minimum actual time aggregate retrieves the minimum good raw value within the interval [s,e), and returns that value. The timestamp of the aggregate will always be the start of the interval for every interval.

Example 1

Start: Jan-01-2002 12:00:10 End: Jan-01-2002 12:00:20 Interval: 00:00:05


Timestamp	Value	Quality
Jan-01-02 12:00:35	0	No Data, Bad
Jan-01-02 12:00:40	0	Bad data in the interval
Jan-01-02 12:00:45	0	No Data, Bad
Jan-01-02 12:00:50	50	Raw, Good
Jan-01-02 12:00:55	0	No Data, Bad

Before Aggregate

When the Before aggregate function is called with a timestamp (Start time), the previous valid value before Start time will be fetched. This search is performed between Start time and (Start time MaxDurationSec). The call for the aggregation is initiated by the source client. The custom aggregations do not require any interval value. The default value for MaxDurationSec is 100 days.

Note: To change the value of MaxDurationSec navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Intellution, Inc.\iHistorian\HDAServer. Create a string value with name MaxDurationSec and provide the value in seconds.

Start: Apr-01-2002 12:00:10 End: NA Interval: NA


Timestamp	Value	Quality
Mar-01-2002 12:01:30	98765	Raw, Good

After Aggregate

When the After aggregate function is called with a timestamp (Start time), next valid value after ???Start time will be fetched. This search will happen between Start time and (Start time + MaxDurationSec).

The call for the aggregation is initiated by the source client. The custom aggregations do not require any interval value. The default value for MaxDurationSec is 100 days.

Note:

To change the value of MaxDurationSec navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Intellution, Inc.\iHistorian\HDAServer. Create a string value with name MaxDurationSec and provide the value in seconds.

Start: Feb-01-2002 12:00:10 End: NA Interval: NA


Timestamp	Value	Quality
Mar-01-2002 12:01:30	98765	Raw, Good

Nearest Aggregate

When the Nearest aggregate function is called with a timestamp (Start time), the nearest valid value of Start time will be fetched. This search is performed between Start time and (Start time MaxDurationSec). The call for the aggregation is initiated by the source client. The custom aggregations do not require any interval value. The default value for MaxDurationSec is 100 days.

Start: Feb-01-2002 12:00:10 End: NA Interval: NA


Timestamp	Value	Quality
Mar-01-2002 12:01:30	98765	Raw, Good

GE Interpolative Aggregate

The purpose of the interpolated aggregation is to return meaningful data for a time interval where raw data is not present. The value at a datapoint is estimated based on the raw data present at other datapoints.

For interpolative aggregate to return meaningful data, good values should be present at the boundary conditions.