6-4 REAL TIME PLOT

The real time plot program (RTPLOT) provides real time plot capability for all <I> processors, plotting up to six points versus time. The time scale can be adjusted by the user, from a minimum of two (2) minutes up to many hours.

6-4.1 Format

RTPLOT uses a data entry form similar to the forms used elsewhere in the <I> processor to specify plotting parameters. The parameters for the real time plot are as follows:

• Elapsed time: Enter the desired elapsed time on the plot in hours and minutes. The minimum time is 2 minutes. The

plot allows for a range of up to 99 hours, but typically the range will not be more than one hour. (See the short term trending option in Section 6-3.)

• Unit Names and Point Names: Enter the unit name and point name for each point (up to six) to be plotted. If the unit

name is left off, the current selected unit will be used. Unit names must be specified in order to see information from more than one unit at once. (Example: MW and MVAR output from multiple turbines.)

• Low and High Plotting limits: Enter the engineering units values for the low and high plotting limits for each point.

The graphs will be drawn with the axis labeled according to these low and high plotting limits.

6-4.2. Notes and Considerations

The CHECK FORM target can be used to check the data entered on the form. Invalid fields will be highlighted in yellow. To draw the plots, choose the DRAW PLOT target. The DRAW PLOT target will do a CHECK FORM

first, and only draw the plot if all fields are valid.

When drawing the real time plot, the current value will always be plotted in the right side of the graph. When the trace reaches the right axis, the graph will "roll back" so that the current trace is shown in the right side of the graph, and the left side of the graph is back-filled with the previous data. For plots of up to one hour, the rollback time will be half the total time. For plots of over one hour, the rollback time will be 30 minutes.

An option in the <I> processor is a special package called Short-Term Trending (see Section 6-3). Once the

ST_TREND.DAT file is edited, the <I> starts collecting data on the points in the file. When Real Time Plot is selected, the <I> uses the values stored in memory to fill up the graph to the current time. If points not in ST_TREND.DAT are selected for Real Time Plot, there will be no history available, but they will be plotted starting when DRAW PLOT is clicked upon. The real time plot uses the time of the <I> processor to draw the initial time axis. Make sure that the time of the <I> processor is close to the time set in the units (within a minute) so that the information shown on the real time plot starts near the midpoint of the graph when the program is first run. If the <I> processor is ahead of the unit time, the real time plot will start too far to the left, possibly even off the graph.

If points are plotted from multiple units and the times in the Mark Vs are not set the same, the X-AXIS position of the points being plotted will be different. The real time plot program will roll back the graph to when the first point hits the right axis. If communication is lost with a unit, all points plotted from that unit will have their point names shown in reverse video. When communication is re-established, the point name will revert to normal video.

Targets are included for PRINT REPORT and SAVE REPORT. The reports contain a list of times and values that were used to make the graph. These reports are in ASCII form, and can be imported by some computer systems for further analysis.

The real time plot program can also start with the data plot instead of the form displayed by having the parameter "/GO"

added to the menu data file. The program will check the form, and if all entries are valid it will present the plot instead of the form. If any entry is invalid, the program will highlight the field and remain in the form.

The resulting menu file would be as follows:

" REAL TIME PLOT" "g:\exec\rtplot.exe" "/GO"

6-4.3. Loading of PreSaved Forms into the Real Time Plot

The Real Time Plot program produces a form on which the user can indicate the elapsed time of the plot and the points to be plotted. A new option allows a set of these forms to be saved in an ASCII file. When the Real Time Plot program is started, the name of one of these PreSaved Forms can be passed to it as a command line parameter. The program will look for that form definition in the file, and if it finds it will go directly to the plot.

6-4.3.1. THEORY OF OPERATION. The Real Time Plot program looks to see if a command line option was included when the program was invoked. If no command line options are found it proceeds to put up the user input form. The contents of the form will be the contents of the form from when the user last ran the program. If a command line option was included on the command line, it will be taken to be the name of a PreSaved Form. PreSaved Forms are defined in a special PreSaved Form file located in the F:\RUNTIME directory. This ASCII file defines a list of PreSaved Forms, which include information to fill in the Title, Elapsed Time, and point list to be entered onto the user entry form. The form is then checked for validity. If any fields on the form are invalid (such as an invalid point name), the user will be left editing the form with the invalid fields highlighted. If all fields in the form are valid, the plot will be displayed.

The PreSaved Form file for the Real Time Plot program is an ASCII file (F:\RUNTIME\RTPLOT.PSF). This file should be edited using an ASCII editor to define the PreSaved Forms desired for each site. There is no limit to the number of PreSaved Forms that can be put in this file. Each PreSaved Form is given an OPTION name, which is used as the command line parameter to the Real Time Plot program.

6-4.3.2. FORMAT. The F:\RUNTIME\RTPLOT.PSF file contains a set of PreSaved Forms in an ASCII format. Each PreSaved Form is started with an OPTION line which specifies the name of this PreSaved Form. The OPTION line starts with the keyword OPTION in column one (1). The name of the option follows inside a set of quotes. (Quoted strings are used because the option can include embedded spaces.)

OPTION "Option name"

Each OPTION has a set of parameter lines that follow to define the various parameters used to fill in the form. These lines must be indented by at least one space under the OPTION line. The parameter lines include:

TITLE "<title>"

The TITLE line defines the title centered at the top of the screen. It is a quoted string that can be up to 32 characters long.

ELAPSED "<delta time>"

The ELAPSED line defines the elapsed time of the plot. The <delta time> parameter is a normal delta time

string. It is enclosed in quotes since delta times do include a space. The format of a delta time is: DDDD HH:MM:SS.CC. The delta times for real time plots usually range from 2 to 60 minutes.

The POINT line defines a trace to be included on the plot. The definition of the point matches the fields of the form. One POINT line is included for each trace on the plot.

The <unit> parameter is the name of the desired unit. If this is not included, then the point will be displayed from the currently selected unit. This is a quoted string since the unit name can be blank.

The <signal> parameter is the name of the signal to plot. This must be the Mark V signal name; it cannot be a synonym. (The synonym name, however, is what the user will see on the screen.)

The <low_counts> and <high_counts> parameters are the raw counts for the range of the Y axis. These are specified in raw counts so that the values are valid no matter what engineering units the user has selected.

Figure 6-10 is a sample PreSaved Form data file (F:\RUNTIME\RTPLOT.PSF) that defines a plot of the Plant Output to be the MW and MVAR traces of the two units over a half-hour period. Lines that start with a semicolon are taken to be comment lines and are ignored.

6-4.3.3. USE OF THE PRESAVED FORM IN THE MAIN MENU. To create a main menu option that includes the use of a PreSaved Form, include the name of the PreSaved Form as a parameter to the Real Time Plot (RTPLOT) program. The PreSaved Form name is not case sensitive, so that upper, lower, or mixed case can be used.

For example, to create a main menu option for the Plant Output sample in Figure 6-10, the following addition to the main

menu data file (F:\RUNTIME\MENU.DAT) would be made:

" Plant Output Plot" "g:\exec\rtplot.exe" "Plant Output"