The following host processes comprise the Trend System:

• TrendMgr – the trend manager process

• TrendGsm – the data acquisition process acquiring data from global shared memory regions

• TrendSvr – the server process that services client requests for trend data

• TrendTrig – the server process that manages historical trend data acquisition

The following screens are available as part of the Trend System:

• TrendX – trend display and analysis

• TriggerMgr – trigger configuration and activation

• TrendFileMgr – historical trend file manager

A historical trend trigger is the definition of an event along with a list of data to be recorded when that event is triggered.  An event is triggered when a set of variables meet some prescribed conditions.  In an aluminum smelting plant, for instance, a trigger could be defined to capture data during an anode effect.  The trigger could watch for when the pot resistance gets too high, and when it does record a set of data including the pot resistance, volts, and line amps.  Once this trigger is configured in the historical trend system, all anode effect events would be captured to individual historical trend files on disk for later review.  

Once a trigger has been activated, the historical trend trigger system monitors each of the trigger conditions and continuously evaluates each of them to determine when they have all been met. During this time the trigger is Waiting for trigger event detection.  If this occurs, and all trigger conditions are met, then data collection begins and the trend system begins to write data to the file.  This will continue until the trigger conditions are no longer all met.  At this point the data file is closed and left on the disk for later review.

Several options are available to enhance data collection:

• A pre-trigger time period may be configured so that when a trigger event is detected the trend system will actually go backwards in time to retrieve the data leading up to the event and save this in the historical trend file before the data for the event itself.  In many cases this information is crucial for determining the cause of a given event.

• A post-trigger time period may be configured so that once the trigger conditions are no longer satisfied the trend system will continue to record data for a period of time and append it to the historical trend file after the data for the event itself.  In many cases this information is useful for determining how the control system reacts after a given event.

• A maximum trend time period may be specified to keep file sizes small and manageable.  This value limits the maximum amount of time of historical data that can be stored in a single file; if the event lasts longer than this amount of time then the data recorded for that event will span multiple files.  This option is useful for continuously recording data (i.e. the event is defined as always triggered) and generating files of finite size.

Triggers can be created, modified, activated, and deactivated using the TriggerMgr screen.

Historical trigger files are stored on the host as ASCII text files.  Following is an example file:

[Trigger]
Name=TrackTime
Description=Record the drift constants for the time tracking algorithms.
TagVar=PidCom.rtDrift.filtDrift
PreTriggerTrendTime=30
PostTriggerTrendTime=45
MaxTrendTime=1440
SaveDate=127592326792807993
 
NumTriggerVars=2
TriggerVar0=/TrendGsm/PidCom.rtDrift.bTrack != 0
TriggerVar1=/TrendGsm/PidCom.pcDrift.bTrack != 0
 
NumTrendVars=4
TrendVar0=/TrendGsm/PidCom.rtDrift.filtDrift   PidCom.rtDrift.filtDrift
TrendVar1=/TrendGsm/PidCom.rtDrift.instDrift   PidCom.rtDrift.instDrift
TrendVar2=/TrendGsm/PidCom.pcDrift.filtDrift   PidCom.pcDrift.filtDrift
TrendVar3=/TrendGsm/PidCom.pcDrift.instDrift   PidCom.pcDrift.instDrift

NumScalarVars=2
ScalarVar0=PidCom.rtDrift.filtDrift   PidCom.rtDrift.filtDrift
ScalarVar1=PidCom.rtDrift.instDrift   PidCom.rtDrift.instDrift

The trend manager process is responsible for initializing the trending subsystem, creating the trend global shared memory, configuring the various trend sources, and processing requests for dynamic trend variables.  In addition, TrendMgr monitors the active trends, periodically writing trend data from the memory buffer to the disk for long-term storage and disabling dynamic variables after a specified period of inactivity.  The trending subsystem is configured via an ini file, which is read by the TrendMgr process on initialization.  This file defines each of the various trend sources such as the global common trending process TrendGsm.  

The trend manager process is initialized by a text file passed to it as a command line parameter.  This file is used to configure the internals of the trending subsystem itself.  It consists of several sections described below:

[General]
This section specifies the general parameters for the trending subsystem.

• MaxTrendSrc=2
  Specifies the maximum number of trend sources in the system. The minimum value is 2, which will support both the internal test trend source and the TrendGsm global shared memory data collection trend source. This is sufficient for most systems.

• MaxTrendVar=512
  Specifies the maximum number of trended variables in the system. This number must be larger than the total of the number of static trends, dynamic trends required by historical triggers, dynamic trends required to support various TrendX clients, and additional trending slots required as 'maneuvering room' for adding and deleting various dynamic trends during operation.  Since most of these values aren't known up front, it is recommended that this number be chosen to sufficiently cover the worst case scenario.

• TrendComSizeMB=30
  Specifies the maximum size of the trend global common in megabytes. The trending system requires that the entire trending global common be locked in memory, so this number specifies the amount of available physical RAM that will be allotted to the trending subsystem.  If this number is too small given the maximum number of trended variables specified above, the TrendMgr process will not start but will provide suggestions (via the console LogMsg) for settings that provide adequate space.

• TempDir=\locNtRt\sys\Temp\
  Specifies a temporary directory for the trending system. This directory is used to contain trended data that has been paged to disk, as well as the trending common image for persisting trend data between system shutdown and restart.

• TriggerDefDir==\locNtRt\sys\Trigger\Def\
  Specifies the storage directory for trigger definitions. This is not required if the historical trend subsystem is not installed.

• TriggerTrendDir==\locNtRt\sys\Trigger\Trend\
  Specifies the storage directory for historical trend files. This is not required if the historical trend subsystem is not installed.

• PersistTrends=No
  Specifies whether or not to persist trended data between system shutdown and restart.

[TrendSrcList]

This section specifies the various trend sources configured for a given system.  Each trend source is specified on a single line in this section; this line contains a white space-delimited list of parameters defining the trend source.  Most systems will only have a single entry for the global common trending system, TrendGsm.

The parameters in order are:

• SourceName
  Specifies the name of the trend source.  This name is used to fully qualify a trended variable.

• AllowTemp
  Specifies whether or not the trend source allows temporary (dynamic) variables to be added at runtime.

An example configuration entry for the TrendGsm source is provided below:

#SourceName       #AllowTemp

TrendGsm          1

This hard real-time process samples variables from global common at frequencies up to 50 Hz (20 ms per sample) and buffers their values into memory. Static trend variables are defined through an ini file, which specifies each global variable’s fully qualified name, sampling period, and the number of samples to be stored both in memory and to disk.  Alternatively, dynamic trend variables may be requested at any time during system operation and the TrendGsm will begin buffering the appropriate data. 

The TrendGsm process is initialized by a text file passed to it as a command line parameter. Typically, this file is the same as that used to initialize the trend manager process and containing additional sections for the TrendGsm process. The initialization file parameters are described below:

[TrendGsmVars]

This section specifies the list of statically trended variables for the TrendGsm process. Each variable listed in this section will be trended at all times as long as the TrendGsm process is active. Each statically trended variable is specified on a single line in this section; this line contains a white space-delimited list of parameters defining the trended variable.

The parameters in order are:

• VariableName
  Specifies the data dictionary name of the variable to be trended.

• SamplePeriod(ms)
  Specifies the sampling period of the variable in milliseconds. This number cannot be smaller than the rep rate of the TrendGsm process as specified in the sysProcs.ini file.

• MemPeriod(s)
  Specifies the size of the circular buffer (in seconds-worth of data) that will be stored in memory before the data is paged off to disk. This number must be greater than zero. If DiskPeriod is zero, this number dictates how far back into the past live data will be stored before it is destroyed.

• DiskPeriod(s)
  Specifies the size of the circular buffer (in seconds-worth of data) that will be stored on disk. If this number is zero, no data will be stored on disk. Otherwise this number must be greater than the MemPeriod and dictates how far back into the past live data will be stored before it is destroyed. 

The trend server process accepts TCP/IP connections from remote clients and handles their requests for trended data.  Trended data is requested by source and variable name at a given sampling rate and between a starting and ending time.  The TrendSrv process searches for the requested variable on the list of currently trended variables, returning the desired data if found.  If the variable is not currently being trended, TrendSrv passes a request for dynamic trend to the specified trend source and returns no data; subsequent client requests for this variable will thereafter return whatever data is available.

• Operates as a TCP/IP server process

• Server services requests to port 2250

• Runs at standard or real time 2000 priority

• Does not run at a Hard Real-Time priority

• Receives and processes connection request from client

• Receives requests for set of trend data

• Saves request information associated with a channel for use as defaults for following data requests

• Responds to requests with requested trend data

• Waits in loop for further data requests

The trend trigger process is responsible for monitoring the trending system for user-defined events and recording historical trends to disk for later reviewing.

The TrendX screen is used to graphically display and analyze recorded trend data.  It can be used either as a real-time display of live data as it is collected by the trending subsystem or to playback previously recorded data.  The graph itself is capable of simultaneously displaying any number of variables on up to sixteen separate, individually configured axes.  

The trend graph consists of multiple vertical axes aligned with the same horizontal (time) axis. As data is played forwards in time it will move from the right to the left; the opposite is true when playing data backwards in time.  Though the vertical axes are stacked from top down, the line displayed for a given trend variable may appear within a different axis if the current value of that trend variable is outside the range configured for its associated axis (by default, trended data is not clipped to fit their owner axis).

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The TrendCtrl window in the left half of the display shows the current configuration of the trend graph.  Variables are grouped according to their associated axes as shown below.

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Between the grid and the graph is a splitter bar that can be dragged left and right to trade space between the graph and the grid.  This allows the user to increase the screen space allotted to the TrendCtrl to view all of the variable details at once or, on the other hand, to maximize the display of the graph within the screen.  A short cut for maximizing the textual display is also available. Click the top left corner of the grid on the left of screen to expand (>) or collapse (<) the textual display.

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Most of the trend configuration can be performed in-place in the TrendCtrl grid.  Each row represents either a graph axis or a variable on an axis, and each column displays the properties for the corresponding axis or variable.  The first column is used to perform Drag and Drop of rows.  The rest of the columns are used to display trending information.  Some of the columns are display only while the others show properties that can be edited in-place. The columns are:

• Drag-and-Drop column

• Name (label)

• Cursor1 (display only)

• Cursor2 (display only)

• Delta (display only)

• Variable name

• Variable data source

• Variable display color

• Variable graph line type
  

The first two rows of the grid describe the graph as a whole.  The entire width of the trend graph and the requested sampling period for the trended data can be set by clicking in the associated cell in the grid as shown below:

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Additional axes can be added to the trend configuration by right-clicking in the grid and choosing Insert Axis.  Once an axis has been added to the configuration, the following properties can be set:

• Axis Label
  Double click the Name column of an axis row to start editing the label of the axis.

• Axis Scaling and Percentage
  Axis scaling and percentage are displayed on the selected axis row in Variable column. Click the cell to display axis scaling and percentage editor. Double click each cell to start editing. Click anywhere outside the editor to exit the editor. At this point the Trending Set is modified and trending will be restarted. The new values will be saved to a trend file if the Trend Set is saved.

Edit axis percentage will automatically recalculate the percentage of each enabled axis. The minimum percentage value is 5%. When the percentage value of an axis is increased the percentage of one or more axes may be reduced starting from the last axis. When the percentage value of an axis is decreased the additional percentage will be evenly distributed to all axes starting from the first axis.

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Variables can be inserted into an axis by right-clicking in the grid and choosing Insert Variable.  A variable will be inserted into the trend configuration above the selected row.  Once a variable has been added to the configuration, the following properties can be set:

• Variable Label
  Double click the Name column of a variable row to start editing the label of the variable. Click anywhere outside the cell to end editing. At this point the Trending Set is modified and trending will be restarted. The new values will be saved to a trend file if the Trend Set is saved.

• Variable Name
  Double click the Variable column of a variable row to start editing the name of the variable. Click anywhere outside the cell to end editing. At this point the Trending Set is modified and trending will be restarted. The new values will be saved to a trend file if the Trend Set is saved.

Click the button in the variable name cell to use data dictionary to select one or more variable names. Double click an empty variable name cell will automatically load the data dictionary. If one or more variable names are accepted the Trending Set is modified and trending will be restarted. The new variables will be saved to a trend file if the Trend Set is saved.

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• Variable Data Source
  Double click the Source column of a variable row to start editing the variable data source. Click anywhere outside the cell to end editing. At this point the Trending Set is modified and trending will be restarted. The new values will be saved to a trend file if the Trend Set is saved.

Click the button in the variable source cell to use Select Trend Source to select a source. Double click an empty variable source cell will automatically load Select Trend Source. If a data source is accepted the Trending Set is modified and trending will be restarted. The new variable data source will be saved to a trend file if the Trend Set is saved.

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• Variable Display Color
  Double click the Color column of a variable row to start editing the variable display color using a color picker. Pick a color for the variable from list.  At this point the Trending Set is modified and trending will be restarted. The new values will be saved to a trend file if the Trend Set is saved.

If instead of picking a color you click anywhere outside of the color picker or click the color cell again the color picker will be closed and the Trend Set will not be modified.

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• Graph Line Type
  Double click the Line Type column of a variable row to start editing the graph line type using a line type list. select a line type for the variable from list.  At this point the Trending Set is modified and trending will be restarted. The new values will be saved to a trend file if the Trend Set is saved.

If instead of selecting a line type you click anywhere outside of the list or click the line type cell again the list will be closed and the Trend Set will not be modified.

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All columns in the display can be resized simply by dragging the column headers.  Clicking on the 1, 2 or * column headers will expand or collapse all axes in the tree display.

 

Individual axes or variables can be moved within the trend configuration using a drag-and-drop operation on the first (blank) column of the grid.

The two vertical bars, one magenta and the other cyan, represent cursors overlaid on the graph. The cursors are used to select the data points for display in the textual trend variable data presented to the left of the graph. The grid on the left half of the screen displays the values of each of the trend variables lying directly underneath each of the two trend cursors.  In addition, the difference between the two cursor values is calculated for each of the trend variables and displayed in the Delta column in the grid.

Normally, the cursor bars default to the left and right edges of the graph display.  However, they can be moved by placing the mouse over the cursor and left-clicking-and-dragging to the desired position.  There is a Reset Cursors button on the bottom right corner of the screen (also in the graph option menu) to reset the cursors to the left- and right-most positions of the graph, which is especially useful for regaining access to the cursors when zoomed in on the trend graph as described below.

It is possible to zoom into a section of the graph simply by left clicking anywhere on the graph and dragging a box to the left or right, as shown below:

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When the left mouse button is released the graph will zoom into the selected region.  Once zoomed, the original full display can be restored by right clicking to bring up the menu and choosing Undo Zoom.

Mouse over an axis (horizontal bar in the graph) and wait for the resize cursor. Drag the axis and release it should change the percentage of the axis. Verify the percentage change using axis editor. At this point the Trending Set is modified. The new axis percentage values will be saved to a trend file if the Trend Set is saved.

Right-clicking on the trend configuration grid displays a popup menu of available options.

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The following options are available from this popup menu:

• Identify Trace
  When this option is selected the graphical presentation of the variable will be resized to allow it to be located on the display.  Notice the variable graphed in Red on the third axis.

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• Original Configured Scale
  Set the axis max and min values to the values specified in the TrendSet.

• Rescale This Axis
  Calculate a new set of axis max and min values based on the data currently displayed in the graph window.  The graph will be update to use these new values.  After this option has been selected the Cursor1 column display will show “(rescaled)” to inform the user that the originally configured scale has been modified. 

The results of the Rescale are show below -- note the changes to the variable in red plotted on the second axis.

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• Set Current Scaling as Original Scaling
  Update Trend Set to set the selected axis scaling as the current scaling. The new scaling will be saved to a trend file if the Trend Set is saved.
  

• Clip All Display Values
  All of the variables currently graphed for this axis will be ”clipped” to keep them within the window area defined for the axis.  The Clip Off and Clip On results are shown here.  Notice the variable graphed in Red on the second axis.  In the Clip Off mode the graph is visible in both first and third axis areas.  With Clip On the variable graphed in Red is only show for the values that fall within the range of the second axis.
  

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• Insert Axis
  Insert a new axis above the selected axis. Insert Axis without selecting an axis to add a new axis at the end.

• Copy Axis
  Select one or more axis without any variable selected to copy the selected axes. Select one or more axis and all the variables under the selected axes to copy the selected axes.

• Cut Axis
  Select one or more axis without any variable selected to cut the selected axes. Select one or more axis and all the variables under the selected axes to cut the selected axes.

• Paste Axis
  Select an axis to paste the copied axes above the selected axis. Paste Axis without selecting an axis to paste the copied axes at the end.

• Delete Axis
  Select one or more axis without any variable selected to delete the selected axes. Select one or more axis and all the variables under the selected axes to delete the selected axes. Select multiple axes and click Delete Axis to delete all the selected axes.

• Insert Variable
  Select a variable to insert a new variable above the selected variable.
  

Select an axis and click Insert Variable to add a new variable at the end of the variable list of the axis above. This action is not available to the first axis on the list. Insert Variable without selecting an axis or a variable to add a new variable at the end.

• Copy Variable
  Select one or more variable to copy all the selected variables.

• Cut Variable
  Select one or more variable to cut all the selected variables.

• Paste Variable
  Select a variable to paste the copied variables above the selected variable. Select an axis and click Paste Variable to paste the copied variables at the end of the variable list of the axis above. This action is not available to the first axis on the list. Paste Variable without selecting an axis or a variable to paste the copied variables at the end.

• Delete Variable
  Select one or more variable to delete all the selected variables.

• Find and Replace
  Click Find and Replace to show Find and Replace dialog box. Enter Find text and Replace with text. Click Replace All to find and replace for all axes and variables. Click Replace Selected to find and replace the selected axes and variables. The function will search axis labels, variable labels and names and replace any Find text with Replace text.

• Change Source
  Click Change Source to show data source editor. Select a source and click Accept button to change data sources for all variables.

• Display Historical Trend Metadata
  Click Display Historical Trend Metadata to display historical trend metadata associated with the historical data source (if the first variable data source is a historical trend source).
  

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• Automatically Select
  Colors Click Automatically Select Colors to change colors of the selected variables with a predefined color list.

Menu

In the bottom left of the display is a button labeled Menu.

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Clicking this button will navigate back to the most recent menu screen.

TriggerMgr

In the bottom left of the display is a button labeled TriggerMgr.

Clicking this button will display the TriggerMgr screen pre-loaded with a trigger definition created from the current TrendX screen configuration.  That is, all trended variables shown on the TrendX screen will be added in the trigger Trend list.

TrendSet Loader Control

To the right of the TriggerMgr button are a set of buttons used to create, load, save, and delete TrendSets.

A TrendSet is a configuration file stored on the host system that contains all of the configuration parameters for the current trend display.  This allows the user to configure a trend graph, including all of the display variables and axis parameters, and store it on the host for later use. This control panel is described in detail in the TrendSetLoader [LINK] section of this manual.

Trend Playback Controls

To the right of the TrendSet loader control is the TrendPlayback control used to control the playback speed and direction of the trended data.

This control panel is described in detail in the TrendPlayback [LINK] section.

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Reset Cursors

To the right of the trend playback controls is a button labeled Reset Cursors.

Clicking this button will move the two data cursors to the far right and far left edges of the current trend view.  This is helpful for regaining access to the cursors while zoomed in to a small section of the trended data.

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