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Prof. Dr. H. KirrmannABB Research Centre, Baden, Switzerland

Industrial AutomationAutomation Industrielle

Industrielle Automation

4.3.4 OPCHistorical Data Access

4 Access to devices

2007 May, HK

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4.3.4 OPC HDA - 2Industrial Automation

HDA: Overview

OPC CommonOverview: usage and specificationsOPC as an integration tool

Clients and Servers: configurationOPC Technology, client and custom interface

OPC Data AccessOverview: browsing the serverObjects, types and propertiesCommunication model

Simple Programming ExampleStandard and components

OPC Alarms and Events SpecificationOverview: definitions and objectsEventsAlarm Conditions

Automation Interface

OPC Historical Data SpecificationOverview

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Historians: An introduction

Invensys (Wonderware) Archestra

The process databasedecouples the plant from the analysis tools.

It contains recent and historical data.

The role of HDA will become clearerafter a first glance at historians

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Historians Example

GE Fanuc/Intellution iHistorian (iFix...)

data collection, archiving and retrieval

report generationcomputations (e.g. VBScript)secure access (FDA 21 CFR 11)20'000 actions/ s,up to 100'000 data points

Features:

Unlimited Point CollectionSub-Second Data Collection RatesEnhanced Data CompressionTrue Thin Client AdministrationFault Tolerant Architecture

Questions to the historian:

What was the value of FIC101 last week ?What was the flow average during October ?Which were the daily averages in October ?What was the total flow in each month ?How much fuel did we use for the batch ?

Give the answer in form of tables,pie diagrams, spreadsheet, reports

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5/314.3.4 OPC HDA - 6Industrial Automation

Historians: Market

Chemical

Food and Beverage

Petroleum

Pulp and Paper

Pharmaceuticals

Power

Textiles

Waste and Water

Other

21%

13%

21%12%

13%

6%

11%2%

1%

2003 Global Information Management Market by Industry

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Historians: Players

ABB Information Manager (formerly Enterprise Historian, bases on Oracle)

AIP/PPA (embedded) Historian is another product (small player)

AspenTech InfoPlus.21 Complete offering with wide range of accompanying applications and services

Very good user interface

OSISoft PI 3.4

Largest installed base (perceived as de facto standard)

Easy-to-use

Perceived low cost (PI 3.4: 1 Mio data points / 80'000 /s) GE-Fanuc Intellution iHistorian

Relatively new to market. Product created with Mountain Systems

Causing a stir for OSIsoft, AspenTech on pricing

Some small players

Honeywell (POMS) Uniformance

Invensys (Wonderware) IndustrialSQL 8.0 Rockwell Automation (RSBizWare) Historian

Siemens (WinCC) Historian (bases on MS SQL Server)

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Historian implementation

historydatabase

field data

operator actions corrections

log organisation

application

"SQL"

"OPC"

collector

OPC HDAODBC/SQL and OPC HDA arecomplementary

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HDA: Historical Data Access

Field device

OPC HDAServer

HDA Clients

independentprocesses

history

database

Field device

OPC DA Server proprietary

data acquisition

e.g. Event Loggere.g. Trend Analysis

calculations

collector

raw andordered data

hidden

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HDA: Purpose

An OPC HDA server gives access to a historical data base (logs) in which data from theprocess have been collected and time-stamped, possibly through an OPC DA interface.

The OPC HDA interface clients, such as trend analysis, product tracking or data mining,that require ordered access these data logs.

The OPC HDA interface allows to:

- browse the historical data base

- retrieve data through proper filtering, e.g. by date range, by identity, by property

- build aggregates over the retrieved data, such as average, minimum, maximum.

- enter new entries, correct entries or remove entries

- enter / delete annotations in the history data base

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HDA: Raw log

12.3.02 13:40 Gpcpt2ofpbonne 4824

12.3.02 13:40 Cpt2bac 50

12.3.02 13:40 Gpcpt2bac 70

12.3.02 13:40 Gpcptbe2 45

12.3.02 13:41 Gpcpt1bac 151

12.3.02 13:41 Gpcpt1ofpbonne 482612.3.02 13:41 Gpcptae2 45

12.3.02 13:41 Cpt1bac 49

12.3.02 13:41 Gpdefr2 64

12.3.02 13:41 Gpvoydef 2

12.3.02 13:41 Gpr3tempscycleprd 318

12.3.02 13:42 Gpstn1e1 16

12.3.02 13:42 Gpalarme1 0

12.3.02 13:42 Gpalarme2 0

12.3.02 13:43 Gpetatmodemarche 2

12.3.02 13:43 Gptpscycle 1346


12.3.02 13:43 Gpdefgene1 16


12.3.02 13:43 Gptpscycle 317

12.3.02 13:43 Gpdefr2 0

12.3.02 13:43 Gpvoydef 0

12.3.02 13:43 Gpdefgene1 0


12.3.02 13:44 Gpr2tempscycleprd 1992

12.3.02 13:44 Gptpscycle 435

12.3.02 13:44 Gpalarme3 1

12.3.02 13:44 Gpalarme4 1

12.3.02 13:44 Gpalarme3 0

12.3.02 13:44 Gpcpt2ofpbonne 4823

Data in the historical database are identified by their

itemID (here, represented by their name), value, (of the respective type) quality (good, stale, bad), and timestamp (UTC).

By definition, values are registered when they change.(even if data are acquired by periodic polling)

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HDA: How to reduce raw data (even before HDA comes into play)

max

min

exceptiondeviation

time

Tag values are sent to the OPC DA server when they change (on events).

The collector records these data in a log that is organized cyclically.

Since a log has a limited storage capacity, data are reduced by several means:1) if a variable is received more often than the log's minimal storage interval (e.g. 1s),

the log keeps the latest of all values of the interval

2) if (and only if) a received variable changed by more than the "exception deviation"(e.g. 5%, analog values only), it is entered into the log.

3) if a variable changed by less than the exception deviation, it may nevertheless beforced into the log after the log's maximum storage interval (e.g. 4 s) elapsed.

= process value (event) = log entry

min time max time max time max time

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HDA Application: Trend Display

Parameters:

time scale (with possible offset, zoom, pan) amplitude scale (low range, high range, scale units) style: smoothed, stepped, filled (several ways to display the same data) extrapolate: how to display values not received (e.g. because they did not yet change)

log: how were data sampled

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HDA: More logs

Field device Field device

Collector

(OPC DA Client)

OPC DA Server

raw log

log 1 log 2

log 2.1 log 2.2

Data in the log may be:

Measured values (original, from the OPC DA)

Calculated valuesCorrected values (replaced or inserted)Annotations (explanation strings)

XML / CSVother servers

A log registers only one data point !

(log templates can be used for

several datapoints)

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yesterdayd-2d-3d-4d-5d-6d-7 today

HDA: Hierarchical logs

A hierarchical log is built on the data contained in the parent log.To reduce the log size, several aggregations can be applied:- record only maximum, minimum, average over a period, etc...

Actual data

1 mn_7 days log

6 MB

1s_24 hours log:50 traces @ 12 B 52 MB

long-term log1 hour_forever 5.2 MB / Year

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

october

1 2 3 27 28 29 30

octobreseptember

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 2223 24

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HDA role

An HDA server allows to browse the logs and filter the logs to be read.It can filter them according to their attributes, such asname of the datapoints, type of the datapoint, engineering units,....

An HDA server then selects the logs to be read.

An HDA can then read the logs, defining a certain period(Start time, End Time, and the maximum number of entries to be retrieved.

When reading the log, the HDA server can process the log by applying aggregationsThe "min time", "deviation", "max time" rules used to collect raw data is also usedas an aggregation to build new logs.

Therefore, hierarchical logs can be built out of a raw log by an OPC HDA service.

Do not confound aggregates and attributes.....

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HDA: Server

The client can query the HDA server for its capabilities, and in particular:

- which LocaleID (national languages) the server supports (as in DA and AE servers)- which attributes the server supports (the attributes of its items is a subset thereof)

- which aggregates the server support (and the client can request)

- if the server supports correction / deletion of data (synchronous and/or asynchronous)

- if the server supports insertion of annotations (synchronous and/or asynchronous)

Many capabilities of the HDA server are optional.

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HDA: Browsing: structure

Object

Area 52

Object

Area 5

Area 51

Log 1

Log 2

Log 3

root

Like the DA and AE interfaces, OPC HDA server offers a browser with methods allowingto navigate up and down, and to retrieve branches and leaves at each position.

If filters are defined at its creation time, an HDA browser only browse for items withspecific attributes (e.g. Engineering Units = m/s). The filtering attributes are additive.

HDA (contrarily to DA and AE) allows several browsers, each with its different filter.

Leaves

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HDA Browsing and filtering

Set MyOPCHDABrowser = MyOPCHDAServer.Createbrowser

(NumCriteria, AttributeIDs, operatorCode, Filters, Errors

MyOPCHDABrowser.MoveDown (MyOPCHDABrowser.OPCHDABranches(1))

Items = MyOPCHDABrowser.OPCHDAItems

.... list these items

The filter criteria are based on attributes (see the following slides).

Attributes cannot be modified afterwards.

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HDA: General attributes of the items

Code Attributes Description

1 DATA_TYPE data type for the item. See the definition of a VARIANT for valid values (VT_R4, etc.)

2 DESCRIPTION text that describes the item.

3 ENG_UNITS label to use in displays to define the units for the item (e.g., kg/s).

4 STEPPED whether data from the history repository should be displayed as interpolated (sloped linesbetween points) or stepped (vertically-connected horizontal lines between points) data.

5 ARCHIVING whether historian is recording data for this item (0 means no).

6 DERIVE_EQUATION equation to be used by a derived item to calculate its value. This is a free-form string.

7 NODE_NAME machine which is the source for the item. This is intended to be the broadest category fordefining sources. For an OPC Data Access Server source, this is the node name or IPaddress of the server. For non-OPC sources, the meaning of this field is server-specific.

8 PROCESS_NAME process which is the source for the item. This is intended to the second-broadest categoryfor defining sources. For an OPC DA server, this would be the registered server name.For non-OPC sources, the meaning of this field is server-specific.

9 SOURCE_NAME 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.

10 SOURCE_TYPE 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.

11 NORMAL_MAXIMUM upper limit for the normal value range for the item, is used for trend display default scalingand exception deviation limit calculations, should be the normal high value for the item.

12 NORMAL_MINIMUM lower limit for the normal value range for the item, is used for trend display default scalingand exception deviation limit calculations, should be the normal low value for the item.

13 ITEMID item identifier. This is used to allow filtering in the CreateBrowse method.

HDA A ib h ff h d hi d

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HDA: Attributes that affect how data are archived

Code Attributes Data Type Description

14 Max Time Interval VT_FILETIME Specifies the maximum interval between data points in thehistory repository regardless of their value change.A new value

shall be stored in history whenever OPCHDA_MAX_TIME_INTseconds have passed since the last value stored for the item.

15 Min Time Interval VT_FILETIME Specifies the minimum interval between data points in thehistory repository regardless of their value change.A new valueshall be not be stored in history unlessOPCHDA_MIN_TIME_INT seconds have passed since the lastvalue stored for the item.

16 Exception Deviation VT_R8 Specifies the minimum amount that the data for the item must

change in order for the change to be reported to the historydatabase. See OPCHDA_EXCEPTION_DEV_TYPE for thespecific meaning of this field.

17 Exception Deviation Type VT_I2 Specifies whether the OPCHDA_EXCEPTION_DEV is givenas an absolute value, percent of span, or percent of value. Thespan is defined as OPCHDA_HIGH_ENTRY_LIMIT -OPCHDA_LOW_ENTRY_LIMIT.

18 High Entry Limit VT_R8 Specifies the highest valid value for the item. A value for theitem that is above OPCHDA_HIGH_ENTRY_LIMIT cannot beentered into history. This is the top of the span.

19 Low Entry Limit VT_R8 Specifies the lowest valid value for the item. A value for theitem that is below OPCHDA_LOW_ENTRY_LIMIT cannot beentered into history. This is the zero for the span.

HDA S l ti th it

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HDA: Selecting the items

Each server has only one group of items, the collection OPCHDAItems.

By adding an OPCHDAItemID to that collection, the client defines its client handle and

receives the server's server handle.

The OPCHDAItemID (a string) should be retrieved by using the browser (like in DA orAE), since entering a string directly is unsafe.

The server handle is used to access the log.

Read operations are applied to the whole collection OPCHDAItems.

....

Set colOPCHDAItems = MyOPCHDAServer.OPCHDAItems

colOPCHDAItems.AddItem OPCHDAItemID ClientHandle

colOPCHDAItems.SyncReadRaw .....

HDA R di th d t

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HDA: Reading the data

When reading the data, the client has the choice to read synchronously orasynchronously (if the server permits the latter).

The client specifies the time interval (Start time and end time) and whether the endvalues of that interval shall be included.

The client has the choice to read the raw data or to apply an aggregation to the readdata. The aggregations (see next slides) allow to reduce data.

HDA: Aggregates

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HDA: Aggregates

Symbol Description

0 NoAggregate Do not retrieve an aggregate (use only start time - stop time and filtering).1 Interpolative Get interpolated values.2 Total Get the totalized value (time integral) of the data over the resample interval.

3 Average Get the average data over the resample interval.4 TimeAverage Get the time weighted average data over the resample interval.5 Count Get the number of raw values over the resample interval.6 StDev Get the standard deviation over the resample interval.7 MinimumActualTime Get the minimum value in the resample interval and the timestamp of the minimum value.8 Minimum Get the minimum value in the resample interval.9 MaximumActualTime Get the maximum value in the resample interval and the timestamp of the maximum value.10 Maximum Get the maximum value in the resample interval.11 Start Get the value at the beginning of the resample interval (time stamp).

12 End Get the value at the end of the resample interval (time stamp of end of the interval).13 Delta Get the difference between the first and last value in the resample interval.14 RegSlope Get the slope of the regression line over the resample interval.15 RegConst Get the intercept of the regression line over the resample interval, (time start of interval).16 RegDev Get the standard deviation of the regression line over the resample interval.17 Variance Get the variance over the sample interval .18 Range Get the difference between the minimum and maximum value over the sample interval.19 DurationGood Get the duration (in seconds) of time in the interval during which the data is good.20 DurationBad Get the duration (in seconds) of time in the interval during which the data is bad.

21 PercentGood Get the percent of data (1 = 100 %) in the interval which has good quality.22 PercentBad Get the percent of data (1 = 100 %) in the interval which has bad quality.23 WorstQuality Get the worst quality of data in the interval.24 Annotations Get the number of annotations in the interval.

HDA interpolation

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HDA interpolation

time

resample interval of the new log

This is useful to display smoothly trend diagrams.

interpolation is an aggregate used when the time scale of the derived log is smaller thanthat of the parent log.

= parent log= filtered log

HDA corrections and annotations

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HDA corrections and annotations

These features are seldom implemented.

Basically, the values are accessed using the server handles thatOPCHDAItems.AddItem returned.

HDA Automation Model

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HDA Automation Model

OPC CommonOverview: usage and specificationsOPC as an integration toolClients and Servers: configuration

OPC Technology, client and custom interface

OPC Data AccessOverview: browsing the serverObjects, types and propertiesCommunication modelSimple Programming Example

Standard and components

OPC Alarms and Events SpecificationOverview: definitions and objectsEventsAlarm Conditions

Automation Model

OPC Historical Data SpecificationOverviewAutomation Model

HDA: Automation Interface summary

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HDA: Automation Interface summary

An collection containing a series of either OPCHDAValue orOPCHDAEntry objects, representing historical values of an item.

OPCHDABrowsers

OPCHDAServer

OPCHDAItems (col)

OPCHDAItemOPCHDAItem

OPCHDAValue

OPCHDAEntry

An instance of an OPC HDA Server. An OPCHDAServer object must becreated to can get references to other objects.

A collection containing all the OPCHDAItem objects this client has

created within the scope of the OPCHDAServer object

An object that maintains the items definition. Note the Custom Interface

does not provide a separate Item Object.

An object that browses item names in the servers configuration.

OPCHDAValue

An object that extends the OPCHDAValue object to include additionalinformation

An object that represents a discrete historical value for an item or anattribute.

OPCHDAEntry

OPCHDAHistory

HDA: Object Interfaces (1)

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To probe further.

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p

OPC Foundation:Specifications http://www.opcfoundation.org

SoftwareToolbox

Examples in Visual Basichttp://www.softwaretoolbox.com/Tech_Support/TechExpertiseCenter/OPC/opc.html

The Code ProjectOPC and .NEThttp://www.codeproject.com/useritems/opcdotnet.asp

Matrikon

Free client and server:http://www.matrikon.com

WinTechToolkit for an OPC serverhttp://www.win-tech.com/html/opcstk.htm

NewAge Automation

Toolkit for an OPC serverhttp://www.newageautomation.com

To probe further.

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p

OPC Foundation:Specifications http://www.opcfoundation.org

SoftwareToolbox

Examples in Visual Basichttp://www.softwaretoolbox.com/Tech_Support/TechExpertiseCenter/OPC/opc.html

The Code ProjectOPC and .NEThttp://www.codeproject.com/useritems/opcdotnet.asp

Matrikon

Free client and server:http://www.matrikon.com

WinTechToolkit for an OPC serverhttp://www.win-tech.com/html/opcstk.htm

NewAge Automation

Toolkit for an OPC serverhttp://www.newageautomation.com

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AI_434_OPCHDA