ch112-17 historical data collection and trend displays - revb

800xA Minerals Training

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Chapter 17 Historical Data Collection and Trend Displays

TABLE OF CONTENTS Chapter 17 Historical Data Collection and Trend Displays........................................................................................................... 1

17.1 General Information........................................................................................................................................................... 2 17.1.1 Objectives ................................................................................................................................................................... 2 17.1.2 Legend ........................................................................................................................................................................ 2

17.2 800xA Architecture for Historical Functions..................................................................................................................... 3 17.2.1 Data Flow.................................................................................................................................................................... 3 17.2.2 Log Hierarchy............................................................................................................................................................. 5 17.2.3 Configuration Overview ............................................................................................................................................. 6

17.3 History Service .................................................................................................................................................................. 7 17.3.1 History Source Aspect ................................................................................................................................................ 7

17.4 Log Templates ................................................................................................................................................................... 9 17.4.1 How to Create a Direct Log Template ........................................................................................................................ 9 17.4.2 Hierarchical Log Templates...................................................................................................................................... 12

17.5 Log Configuration ........................................................................................................................................................... 13 17.5.1 How to Create a Log Configuration.......................................................................................................................... 13 17.5.2 Check the Data Size.................................................................................................................................................. 15 17.5.3 Presentation Settings................................................................................................................................................. 15

17.6 Reading Log Contents .................................................................................................................................................... 17 17.6.1 Check the History Source ......................................................................................................................................... 17

17.7 Trend Displays................................................................................................................................................................. 18 17.7.1 How to Create a Trend Display ................................................................................................................................ 19 17.7.2 How to Setup a Trend Display.................................................................................................................................. 20

17.8 Operation ......................................................................................................................................................................... 23 17.8.1 Tool Bar .................................................................................................................................................................... 23 17.8.2 How to Change the Time Scope ............................................................................................................................... 24 17.8.3 Table Part.................................................................................................................................................................. 25 17.8.4 Additional Table Columns........................................................................................................................................ 26 17.8.5 XY Plot ..................................................................................................................................................................... 27 17.8.6 Moving Trend Data to MS Excel.............................................................................................................................. 28

17.9 Trend Templates .............................................................................................................................................................. 29 17.9.1 How to Create a Trend Template.............................................................................................................................. 29 17.9.2 How to Setup a Trend Template ............................................................................................................................... 30

CH112-17 Historical Data Collection and Trend Displays - RevB

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17.1 General Information

17.1.1 Objectives

On completion of this chapter you will be able to:

• Set up the history source

• Describe how historical information is collected

• Configure log templates

• Configure logs

• Configure and modify trend templates

• Create and configure trend displays

• Operate trend displays

17.1.2 Legend

< > Indicates a key name.

| Indicates when you go from one menu to a sub-menu.

Bold Indicates a menu name or an option in a menu, or file structures

“ “ Indicates dialog box buttons, tabs, instructions etc.

Indicates start/explanation of student activity


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17.2 800xA Architecture for Historical Functions

The 800xA system supports a full array of historical and reporting functions. Many of these functions such as archiving require the Information Manager software. However, basic historical collection is performed by the Basic Historian in the Connectivity Server and so it is available as a base feature of System 800xA.

In fact, if Information Manager is installed in the system, it gets its data from the Connectivity Server’s basic historical logs using the OPC’s HDA standard protocol. This protocol, unlike the DA protocol, can get multiple values for the same point with one request. If the Information Manager machine is off line for a while, there is no loss of data because it can retrieve the whole time period from the Connectivity Server when it comes back on line.

The Connectivity Server is usually redundant so it is unlikely that data will be lost due to a failure. Both Connectivity Servers are always collecting the data so if one is off-line, it will back fill from the other when it returns to service.

What is a log?

A log is a collection of time stamped (tagged) data. The process or system object from which the data originates is called the data source.

17.2.1 Data Flow

The log is normally stored on a hard disk on the Connectivity Server. The storage size is up to 10,000,000 data points per log. All logs are circular; the oldest data entry is overwritten by the newest when the log is full.

NOTE! Log data cannot be archived, if not using Information Manager.

t0s 10s 20s 30s 2’592’000s

or 30 days

Storage Size

LOG

Storage Interval

Data Source


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Logging can take place as fast as once per second. There is almost no limit to the number of logged data items. But there is always a balance between the rate of logging and the number of data points to be logged – if both are high then the network may be considerably loaded.

Client/Server Network

Control Network

Field bus

Controllers

ConnectivityServer

Field devices

AspectServer

Workplaces (Clients)

Trend displays

Historical data

The data collection is done using the OPC DA standard but the Historian also has the ability to collect data through some proprietary protocols such as the AC 400 Controllers TTD logs.


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17.2.2 Log Hierarchy

A hierarchical log is one whose input data source is another log. The first log is a direct log, with data coming from the OPC Server. The succeeding logs get their input from the first log. The selection of aggregate (algorithm) determines the type of processing done to the data before it is logged.

There is no hard limit to the number of hierarchical levels which can be configured.

t0s 10s 20s 30s 60s 2’592’000s

or 30 days

t0s 60s 120s 180s 180 days

Aggregate

Data SourceStorage Size

OPC

LOG 1

LOG 2

Storage Interval

Example

LOG1 is a direct log, logging data from the OPC server every 10 seconds.

LOG2 is a hierarchical log, logging the time average of the samples from LOG1 over a 60 second time period (6 samples from LOG1).


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17.2.3 Configuration Overview

There are two parts to setting up values to be logged:

Log Template aspect

This aspect is configured in the Library Structure. It determines the size of the log and the frequency with which items are logged.

It does NOT say what should be logged

Log Configuration aspect

This aspect is configured in the Control Structure as part of the object where the signals to be logged are found. It defines which properties (for example Value) on the object/signal to log, and how to log (by referring to a Log Template).

Log Configuration WHAT IS LOGGED

Log Template HOW DATA IS LOGGED

Library Structure

Control Structure


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17.3 History Service

Before any logging can take place the log configurations need to know where to obtain the data.

Just as 800xA has services to provide alarm and event functions, there is a service for collecting history. It is called the Basic History Service and the responsibility is to acquire and make available data for logging. It communicates with the OPC Server to obtain the data coming up from the controller.

The situation is similar to other service set-ups. The History Service is defined in the Service Structure. This service may serve one or more History Service Groups.

The Basic History Service gets installed and configured automatically during system creation. Unless further groups are required there is no work to be done in the Service Structure.

17.3.1 History Source Aspect

Before logging of properties can take place in any structure at least one History Source aspect must be defined. This is done at a fairly high level in the structure. All objects that are descendants (children) of the object containing the History Source aspect inherit this source.

The History Source aspect is required to point to the service group which will be used for all log configurations.

For logging from data inside objects in the Control Structure, it is usual to set up the history source as an aspect of the Control Network, and then all objects below it will use this history source.


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1. Mark the Control Network object in the Control Structure.

2. Add an aspect of type <History Source> to the Control Project and name it “History Source”.

3. Open the “Config View” for History Source.

4. Click on the “Open” button and select the service group “Basic” from the list of the available service groups. This service group is defined in the Service Structure Basic History Basic as explained above.

5. Click onto “Apply”.

The History Source is now configured. All objects and child objects of the Control Project object are able to use this History Source.


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17.4 Log Templates

A Log Template is a re-usable template for building many similar logs. Modifying an existing Log Template, will affect existing logs use that Log Template.

Two default log templates are available for use. The user can also create templates in the default library or create a user library and place the user templates there.

17.4.1 How to Create a Direct Log Template

As a first step, we always have to create a Direct Log template. The Direct Log is the collection of data directly from an OPC source.

1. Select the Library Structure.

2. Mark History Log Templates in the Object Tree and select “New Object” from the context menu.

3. “History Log Template Library” is just a container of log templates (like a folder). You may create a new object of type “History Log Template”.


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4. Select the “Config View” of the Log Template aspect.

5. Create a new Property Log Template by clicking the “Add” button. The first log must always be a direct log.


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6. Select the tab card “Data Collection” and specify how to collect data.

We can specify the amount of data to store in either number of points or length of time.

We can specify the resolution of the collection in terms of a minimum and maximum time for taking a sample, and we can specify an exception deviation. This allows some data compression by not collecting samples that have not changed significantly from the previous. If we leave the Exception Deviation at 0.000%, samples will always be collected at the minimum time.

The Min Capacity and Max Capacity figures at the bottom of the tab show the effect of the decisions we make for storage interval and size based on whether data is collected at the minimum or maximum resolution.

The Aggregates and Bad Data Quality Limit entries at the top are unavailable for a Direct Log. We will see their use in the next section.

7. Select the tab card “Log Definition” and give a new name to the log.

NOTE! Log names should specify collection interval, log capacity and aggregate (if applicable).

8. Apply your changes by clicking onto the “Apply” button and the new template is created.


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17.4.2 Hierarchical Log Templates

A Hierarchical Log is one that uses another log as its source rather than a direct OPC collection. The ultimate source of data is still the OPC collector, but we can use the Direct Log to provide data to the hierarchical log. This provides a lot of flexibility in how we handle the data with regard to compression.

Taking a look at the Data Collection tab of the second level of the hierarchical log, we can decide how to reduce the resolution of the data. The Aggregate entry has many selections from average to standard deviation, summation, interpolation and many others.

The Bad Data Quality Limit specifies what percentage of the samples can be bad and still create an acceptable aggregate. If more than this percentage is bad, the aggregate sample will be marked bad in the hierarchical log.


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17.5 Log Configuration

A Log Configuration aspect is required for each object which contains properties to be logged. It is used to specify the properties to be logged and which log template to use for each property.

Remember that each tag can have many different values associated with it and these are called properties. For example in a PID loop, the signal for the set point, process variable, and control output are all individual properties. Each one of these that we want to maintain history for will need a separate log defined.

17.5.1 How to Create a Log Configuration

1. Open the Control Structure of a project and select any process tag such as a Function Block or a Control Module.

2. Add an aspect of type “Log Configuration” to the Function Block instance and name it “Log Configuration”.


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3. Open the “Config View” of the Log Configuration aspect.

4. Click onto the button “Add Property Log” to create a new log.

5. Select a property from the list and select a template.

6. Click onto the “OK” button. Click “Apply” to close the Main View of the aspect Log Configuration.

There is no reason we cannot have more than one property log configured even for the same property.


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17.5.2 Check the Data Size

After you created a new log configuration and added a property log to it, some new tab cards with different settings exist.

The “Property Log” tab displays log information. The Data Size is the size of the Property Log on disk. It is the sum of the size of all logs. The size of each log file is the sum of the file header and the data storage size.

17.5.3 Presentation Settings

All values are used to display the trace in a Trend Display. These values can be set in either of:

• The Object Type (i.e. in the Property Aspect).

• The Object Instance (i.e in the Property Aspect).

• The Log (in the Log Configuration Aspect).

• The Trend Display.


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The above listed are in override order. For example you can override a value set in the Object Type by writing a value in the Object Instance. Another example is a value set in the Object Type, the Object Instance for presentation attribute or the Log can be overridden in the Trend Display.

To override a presentation attribute the check box for the attribute must be marked. If the check box is unmarked the default value is displayed.

Engineering Units are inherited from the source but can be overridden.

Normal Maximum and Normal Minimum are scaling factors, used for the scaling of Y-axis in the Trend Display. The values are retrieved from the source but can be overridden.

The Number of Decimals are retrieved from the source but can be overridden.

The Display Mode can be either Interpolated or Stepped. Interpolated is appropriate for real values, Stepped for binary.


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17.6 Reading Log Contents

You may read log contents by selecting the function block in the Control Structure, then select the log configuration you created before and choose “Config view”.

Select the logged property you want to read, then click on the tab “Status” and press the “Read” button.

17.6.1 Check the History Source

Check that the history source is working:

Logging will not work Logging is working

Bad news Good news


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17.7 Trend Displays

Trend Display aspects are used to present both historical data AND live data to the operator. The history data and run-time data are seamlessly integrated.

A trend display consists of three areas:

Any OPC property can be logged. That means more than just typical process data can be displayed in a trend display. Diagnostic and system data can also be trended, but of course the most common trends will be process data.

NOTE! Placing a cursor on a trend causes a text box (tool tip) to pop up providing detailed information.

Trace Area

Trend Table

Tool Bar


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17.7.1 How to Create a Trend Display

In general, a Trend Display can be created in any structure. A sensible place to add a trend aspect might be an Equipment or Unit object in the Functional Structure.

Remember that the operators will not be looking for these displays in the Plant Explorer. The reason to configure a graphic or a trend display as an aspect of an Equipment or Unit object is to assist the engineers in keeping track of what they create. Trend displays will then usually be accessed from the graphics.

7. Add a Trend Display aspect to any object by right clicking and selecting “New Aspect”. The aspect category is “Trend Display”.

8. Open the “Config View” of a trend display aspect and disable the check box “Default”. Select the Trend Template from the drop down box.

9. Click “Apply” and close the Config View.


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17.7.2 How to Setup a Trend Display

Many of the values in the trend table area provide the ability to click on them and enter new values. Some spaces provide pull down selections when clicked on, and some provide ellipsis buttons (…) which, when clicked on call browsing pop-ups.

Some of the fields are not configurable since they contain the live values and time stamps when the trending is active.

10. Double click on the aspect to launch the Main View.

11. Click the check box to at the far left of each row are to activate or deactivate the trend display for that object. This allows the operator to temporarily show only one trace for the sake of clarity in the case of overlapping lines. Un-checking the box does not deactivate collection of the data. It only clears the trace from the display.


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12. Click in the “Object” field and browse for an object.

13. Select the relevant aspect, which is in most cases “Function Block” or Control Module”.

14. Click on the “Property” field and select a property from the list. If no aspect is selected the drop-down menu includes all available properties on the object, otherwise only the properties from the selected aspect.

If necessary you can expand the column. Move with the mouse to the right column end till the mouse cursor changes its design. Then click left and drag the column as large as you want (similar to the handling in Microsoft Excel).

NOTE! If the shift key is pressed only logged properties will appear in the list.


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15. Select the “Log Name”. A drop-down menu provides a selection for several sources for the values in the display. It shows all logs defined by the Log Configuration Aspect for this particular object. If there is no Log Configuration aspect on the selected object, the user can select TRIM and SEAMLESS (the TRIM log is always available).

Once we have created historical collections, there will be multiple choices for the source of the data. We can have real time trending as well as trending maintained by the Connectivity Server and additional history maintained by the Information Manager. We could select one of these sources for the data, or we can set the selection to SEAMLESS. This will instruct the system to find all possible sources and plot them as a seamless set of data. It will be indistinguishable to the user where each part of the data is coming from

NOTE! A trim curve is the term used for a real time trend.

16. The trend will now be visible. Click into the field “High Range” and set it.

17. Click onto the “Save” button to save your changes.


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17.8 Operation

17.8.1 Tool Bar

The Tool Bar contains buttons for frequently used functions to operate the Trend Display.

• The Show/Hide Table button shows or hides the Trend Table. When the table is hidden, it is replaced by a small table, showing trace colors and logged object in the form object:property,log name. This state is part of the configuration and can be saved with the Save button.

• The Block/Unblock button toggles the updating of the graphical view. A pressed button means the view updating is paused. By clicking the button again the view is unblocked.

• Use the Move Scope left/right buttons, to pan the graphical view in the selected direction. The buttons move the scope by 25% of the current time scope.

• Zoom in/out buttons let you zoom in or zoom out around the center point of the scope. Zooming out increases the scope by 50%. Zooming in decreases the scope by a third.

There is a vertical green line which is called the ruler. It can be moved anywhere on the display by left clicking on point in time.

• Clicking the Ruler button turns on the selected ruler.

• Move Ruler: Only the applicable buttons are available, depending on selected ruler. These buttons moves the ruler left, right, up or down.


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• The Magnifying glass button toggles the magnifying glass mode. It will set up the magnifying glass area with a default start time and end time, using 35 percent of the area for the magnifying glass. It is very useful to analyze a process upset.

17.8.2 How to Change the Time Scope

Using the direct entry of a time scope and display time is another way to pan and zoom. It can be much faster than using buttons when the time is far in the past.


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17.8.3 Table Part

The figure below is an explanation of the main table part of the trend display.


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17.8.4 Additional Table Columns

Below is a description of some other important columns. Details can be found in the On-line help or in the product manuals.

Column Description Log Name A drop-down menu shows logs defined by the Log Configuration Aspect. If there is no

Log Configuration aspect on the selected object, the user can select TRIM and SEAMLESS.

Filter The default filter value is zero (0), indicating no filter. The value must be between zero (0) and one (1), not including one. Only values above 0.5 have a noticeable effect. The filter works as a low-pass filter, effecting noise reduction for the trace. The visible result is that the trace appears smoother. The closer this value is to one (1), the stronger this effect will be. With a value very close to one (1), the trace will appear almost flat. See example below.

Time Offset The time offset used for the trace. The default is zero (0). The format used by the cell is yy:mm:dd HH:MM:SS. If this offset is positive, the trace is shifted right. If the offset is negative, the trace is shifted left.

Style To change the style, select from the drop-down menu of styles. The available styles are shown below.

In addition to these, there is Normal. If this style is selected, the actual style depends on what is specified for the display mode presentation attribute.


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17.8.5 XY Plot

An XY-plot is a trend that use a trend variable instead of time on the X-axis. It draws one signal as a function of another signal (instead of plotting it as a function of the time).

Use the column “Pair Property” to define an index used for pairing XY plot.


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17.8.6 Moving Trend Data to MS Excel

The capture data function lets you copy data from the Trend Area, and then paste the copied data into a third party software application such as Microsoft Excel.

18. Use zooming and move the scope to display the desired interval in the Trend Area.

19. Left click in the trace area of the Trend Area.

20. Copy the data into the Windows paste buffer by pressing Ctrl+C.

Now you can paste the selected data to an external application (for instance, Microsoft Excel). Go to the external application and use the Paste function to copy the data. If the Trend Display is zoomed out you can not be sure to get the sampled data, instead it might be interpolated.

An example of captured data being pasted into Microsoft Excel is shown below.

The columns display time, value and status word for each point in the trace.


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17.9 Trend Templates

When adding a trend display in the previous section, there were several characteristics of the display that were not configurable. For example, we could not change the colors of the traces, the number of traces, or content of the columns in the trend table area.

Fortunately, these characteristics are configurable in the template used for the trend display

NOTE! Modifying an existing Trend Template will not automatically affect existing Trend Displays that have been created using that Trend Template.

.

Just as the case of alarm lists, there are templates in the Library Structure for trend displays. We can modify the defaults or create new ones. As in the case of alarm lists, it is much better to leave the defaults alone and create new ones in order to avoid losing custom work when upgrading software revisions.

17.9.1 How to Create a Trend Template

The trend templates are located in the Library Structure.

There are actually two types of objects shown, a Trend Template and a Trend Template Library. The Library is just a container for the templates. Rather than add to the existing library, which is called “Default Trend Templates”, it is better to create a user library to add all the custom templates to.

21. Mark the Object called Trend Templates and create a new child object of category “Trend Template Library”.


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22. Mark the new library object and create a Trend Template object as a child.

17.9.2 How to Setup a Trend Template

To configure the characteristics of the template, we select the Trend Template aspect of the Trend Template object in the Trend Template Library.

23. Just double click the trend template aspect of the of user defined trend template.

24. The General tab is used to set the default time scope, the table size and the number of trace areas.

In the default templates we have seen, there was only one graphical area, and all the traces appeared in that area. It is possible to have multiple separate graphical trace areas defined and to determine how much space is devoted to each. We can also determine what time scopes will be available in the display. The one with the check mark is the one that will come up when the display is called. If we are creating an XY plot template, we can select a picture (jpg, bmp, wmf, gif, etc) to appear as the background for the plot. A good use for this capability is to have an ideal curve as the background picture. The actual curve is then plotted against this ideal. Or we could have tolerance limits as the background picture.


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25. The color tab is used to set the number of traces, assign the traces to trace areas and set colors.

In addition to selecting the colors, we can configure the grid lines. We can determine the resolution of the grid and whether the minor divisions are full lines or just ticks along the edge. One thing to notice is that each trace has a heading called area. This is the graphical area in which the trace will appear if we configure more than one. By default all traces are selected in area one. Just because we configure more than one area, it doesn’t mean any traces will appear in the second area unless we change the assignment. This can be changed by clicking on the number.


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26. The Columns tab is just like the alarm list column selector.

It may be desirable to simplify by eliminating some of the columns in the custom template. The widths of the columns can also be adjusted. This is only the width of each column as it appears when the display is called up. The columns can be stretched and shrunk with the mouse while viewing the display.

If we modify the trend template at some later point, the changes will not automatically update in the trend displays that are based on that template. We will have to reselect and apply the template to the display using Config View again.

ch112-17 historical data collection and trend displays - revb

Documents

log configuration

log hierarchy

reading log contents

hierarchical log templates

historical data collection

direct log template

data flow

data size