- Charts -
Charts are used as a convenient means of displaying plant data in graphical form. They behave in a similar manner to a mechanical recorder and paper. The chart may be used to display historical recorded data (historical chart) or real time plant data (current chart).
There are two types of chart available in DataManager.
A standard chart which is invoked in its own window. This type of chart may be moved, zoomed and may have a databox which shows historical or real time values.
A chart object is a chart which is embedded into a drawing. This type of chart may not be moved or zoomed. Neither can it have a databox.
Historical charts use data, which is recorded to the computer hard disk at various intervals by the logger. This data is discrete time snapshots of the actual plant information. When an historical chart is displayed, the chart recovers the recorded data for all the traces covering the chart time period. The user is then free to use the chart as a 'window', moving this window around over the recovered historical data as required. If the chart duration is changed the chart automatically loads the historical data for the new duration.
Trend charts use a combination of historical and current data to show plant behaviour in real time. If the current time and date exists on the current chart window then the traces will grow in real time as the plant data changes. This real time update will occur approx. every 4 seconds.
When a chart is initially displayed the plant data is displayed from left to right across the screen. The horizontal (X) axis is time and this is automatically marked in sensible intervals across the bottom of the chart. The vertical axis (Y) is data value and this is also marked in sensible interval at the left of the chart. Since each trace may use a different Y scaling, the user may select the different axes by clicking on the axis selector buttons below the Y axis. The axis will then be suitably re-labelled in the new traces' colour.
The chart has many advanced features which allow the user to closely examine the displayed data. The user may move forward or backward in time using the time scrollbar at the bottom of the chart or up and down using the Y axis scrollbar at the right of the chart see Moving around the chart . Alternatively the user can zoom in and out. To display historical or current digital data the Data Box may be used along with the Trace Cursor to display actual plant values.
To zoom in on an area of the chart, the user should use the mouse to draw a box around the area of interest. Position the mouse cursor at one corner of the box and press the left mouse button. Whilst still holding down the button, drag the mouse to the opposite corner to draw a dotted grey rectangle. This has now defined the zoom area.
Zooming
To actually zoom in simply left
click the mouse while pointing anywhere inside the dotted rectangle
and the chart will instantly zoom such that the dotted rectangle now
fills the available chart area. To cancel from the zoom left click
the mouse which pointing anywhere outside the dotted rectangle. While
zoomed in the user may move the chart zoom window as required by
using the scrollbars.
The data box is used to show actual values for the chart traces and can operate in one of two modes.
Current Values Databox
To show the currently measured
values for each of the chart traces invoke Data Box|Current values
from the chart menu bar. The Databox will then appear.
The top line of the databox shows the current time and date in black. Subsequent lines show the trace descriptions and current values for each trace used on the chart. These values update approximately every 4 seconds.
The databox may be moved or re-sized as required so as not to obscure the chart information.
To remove the data box, click on the black cross at the top right of the box.
Historical Values Databox
To show the historical values for
each of the chart traces invoke Data Box|Historical values from the
chart menu bar. The Databox will then appear and the normal chart
cross hair cursor will change to the trace cursor.
As the trace cursor is moved over the chart the top line of the databox shows the time and date in black of the trace cursor position. Subsequent lines show the trace descriptions and historical values for each trace at that time. These values update automatically as the cursor is moved.
The databox may be moved or re-sized as required so as not to obscure the chart information.
To remove the data box, click on the black cross at the top right of the box.
Trace
Cursor
When the Historical Databox is
displayed, the normal chart crosshair cursor changes to a pair of
lines extending right across the chart. This is the trace cursor.
This makes it easy to position the intersection of the lines on a
point of interest and, while tracing the lines back to the axes, read
off the time and value at that point. The historical data box also
shows all the trace values at the trace cursor time.
Chart
Setup
This dialog is used to set up
some general features of the chart.
Grid Display Checkbox
Check this box to display the
chart grid.
Chart Title
Enter the title of the chart.
Background Colour Button
Press this button to select the
chart background colour. Remember that a colour that looks good on
the screen may prove to be unsuitable when the chart is printed. It
is best to stick to very light colours for this reason.
Transparent Checkbox
Check this box to cause the chart
to have a transparent background. This is only applicable to chart
objects embedded into drawings and has no affect on window based charts.
Grid Colour Button
Press this button to select the
chart grid colour
Axis Labelling Font Button
Press this button to select the
font and size of the text used for chart axis labelling. Any font
resident on the system may be selected.
Keep Current Time on chart Checkbox
Check this box to force the chart
to automatically keep the current time and date visible on the chart.
This does not apply of course when zooming in.
Historical Data to keep
Enter the minimum amount of
historical data to keep visible on the chart. This is only applicable
when the Keep current time on chart checkbox is ticked. When the
chart trace reaches the right hand side of the chart, the chart will
be redrawn with the current time positioned at this percentage of the chart.
Show Relative Times on Chart
Check this box to force chart
time displays to be relative to the chart start time..
The trace setup dialog is used to specify the traces, which are to be shown on the chart. Up to 32 traces may be shown simultaneously on a single chart.
Traces List
This box shows a list of the
traces that currently exist on the chart along with their
descriptions and units.
Select a trace by clicking on the
line required. The data for the selected trace is shown below.
To add a new trace
Fill in the required trace
details in the boxes below and press the Add button. The new trace
will appear in the traces list. Sometimes it may be easier to select
an existing trace, edit its parameters and then add the trace by
pressing the Add button.
To edit an existing trace
Select the trace to be edited by
clicking on it in the traces list. Edit the parameters below and then
press the Change button to apply your changes. If the Change button
is not pressed the changes will not be applied to the selected trace.
To delete an existing trace
Select the trace to be deleted by
clicking on it in the traces list. Press the Delete button to delete
the trace from the list.
Tag Name selector box
Select the tag name whose data
you wish to display for the currently selected trace. This may only
be tags which hold numeric data. String tags are not allowed on charts.
Description edit box
Enter the trace description
required on the chart.
Units edit box
Enter the units of measure for
the trace eg mBar or C etc.
Scale range boxes
Enter the upper and lower scale
limits required for the trace. eg 0 to 100.
Trace type buttons
Since the system records
historical data in discrete time snapshots (configured in the
logger), there are two ways in which the data can be displayed on a
chart. The ramp mode assumes that the value of the recorded parameter
changes continuously between one record and the next. This is more or
less true for analog values but not for digital values. Use the trace
type buttons to choose the display mode required.
Ramp button
Check this button to cause the
chart to linearly interpolate between discrete recorded values. This
has the affect of smoothing the trace and is the normal default setting.
Step button
Check this button to turn off the
ramp setting. This will cause the trace to be displayed as a
staircase. This is particularly useful for showing digital
information on the chart.
Line Group
Use the elements in this group to
specify the colour and type of the trace.
Colour Button
Press this button to change the
colour of the currently selected trace. When pressed the standard
windows colour selector will appear.
Select the required colour and press the OK button. The sample box will immediately show the effect of your colour change.
Style Button
Press this button to change the
line style of the currently selected trace. When pressed the line
style selector box will appear. This box gives a wide choice of line
styles, select the line style required and press the OK button. The
sample box will immediately show the effect of your style change.
Sample Box
This box shows a sample of your
line, colour and fill style settings.
Fill Group
Use the elements in this group to
specify any filling requirements for the selected trace.
Fill type radio buttons
None
Check this button if no fill is
required for the current trace. If None is selected then the trace
will be displayed as a line only.
Value
Check this button to cause the
chart to fill in between the trace and a fixed value on the chart.
Enter this value in the edit box adjacent to the button.
Tag
Check this button to cause the
chart to fill in between this trace and another trace displayed on
the chart. Enter the tag name of the other trace using the selector
box adjacent to the button. Please note that this trace must already
be present in the list for it to be selected. This option is
particularly useful to display a shaded band on a chart, this could
be used for example to show a hottest/coldest band.
Pattern button
Press this button to select the fill pattern to be used. A range of 8 fill patterns will be displayed. Select the pattern required and press the OK button. The sample box will immediately show the effect of your fill pattern change.
This dialog box is used to set up the chart start and end times.
Start Time Group
Date
Enter the chart start date in
DD/MM/YYYY format.
Time
Enter the chart start time in
HH:MM format (24hr clock).
Now Button
Press this button to
automatically set the chart start time to the current time and date.
-1h Button
Press this button to subtract 1
hour from the chart start time.
Chart Duration Group
This group specifies the time
duration for which the recorded data is loaded into memory.
The valid limits are 1min to 7days.
Days Selector
Use the up down buttons to select
the number of days to display.
Hours Selector
Use the up down buttons to select
the number of hours to display.
Mins Selector
Use the up down buttons to select
the number of minutes to display.
Page Duration Group
This group specifies the time
duration which is actually shown in the chart window.
The valid limits are 1min to
7days and this duration must be less than or equal to that set for
the chart duration above.
Days Selector
Use the up down buttons to select
the number of days to display.
Hours Selector
Use the up down buttons to select
the number of hours to display.
Mins Selector
Use the up down buttons to select
the number of minutes to display.
This dialog allows you to export part of a chart to a file in CSV format. This CSV file could then, for example, be imported into Excel or Word for further analysis.
Chart
Markers
Chart markers are
used to mark positions of special interest on the chart. Two markers
are available and these are shown as thick vertical lines with the
marker number in a box at the bottom. When markers are used the chart
Databox will be expanded to show the data values at the marker
points. If two markers are used then the databox will also show the
time difference between the markers and the average rate of change
for each trace between the marker times. The markers may be placed
anywhere on the chart area and may be in any order required.
Note: Markers are
NOT available on embedded chart objects.