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tabfilter 93



tabfilter - An interactive data quality selection and display task for ST tables.


tabfilter tables


List of ST tables used for display and data quality selection. Table names may be specified using wildcards such as table[1-7], which loads all existing ST tables from to
limits = ""
An optional ST table containing hi/low limits for any number of monitors.
gap = 5
Allowed number of missing nominal time intervals before considering the gap in reported data as a day gap. A nominal time interval is defined for each table from the difference of the first two values of the time column unless specified in the ST table by the header keyword DELTIME .
imode = "line"
Initial interactive mode, either gcur or line mode.
device = "stdgraph"
Output graphics device: one of stdgraph , stdplot , stdvdm , or device name.


Tabfilter is a macro task that calls the task dqselect in the euv.euvred package. It is available in xproto for convenience to Xray Users.

This task is a data quality selection task allowing the user to interactively display time dependent data stored in ST tables and create time filters according to user-supplied limits. Once the ST tables are loaded by tabfilter, a variety of commands are available to the user to display and utilize the information contain within the ST tables.

Tabfilter will work with any ST table, though at this point it is best adapted for indexed ST tables containing a monotonically increasing index or time column. The indexed ST table has a few features which are taken advantage of by tabfilter.

Each ST table must have an index or time column to represent the independent data set for the subsequent columns of the ST table. Tabfilter assumes that the first column of the ST table serves as the index column, unless the index column name is specified by the ST table header keyword TIME . All other columns of the ST table are considered monitors that are dependents of the index/time column.

Tabfilter assumes the existence of a nominal time interval for each ST table. The time interval is derived from the first two values of the index/time column unless the numerical value is specified by the ST table header keyword DELTIME .

Data which should be treated as rates can also be indicated within an indexed ST table using the RATE000 header keyword. Such columns will have their values divided by the nominal time interval to produce rate values.

Using indexed ST tables allows tabfilter to display each of the columns correctly.

Tabfilter's main purpose is to assist in data quality selection. This consist of generating good time filters on the basis of data quality. Where a monitor describes the quality of data recorded by an instrument, limits can be set when data quality is suspect. Based on these limits, filters can be generated for use in filtering out the poor quality data produce by the instrument.

To take a specific example, consider an instrument which is kept track of by various monitors. Each monitor reports its value at regular time intervals and is stored in a column of an indexed ST table. Here the time that each value is reported acts as the index column. If a monitor conveys the state of the health, then certain values of the monitor define the borders of a healthy instrument. These values define the limits for which the monitor indicates the instrument is in good health. The corresponding times for which the monitor values are within the limits are called good times . By generating start and end times for all the good time intervals, a time filter is created which can be used to filter out questionable data reported by the instrument. Tabfilter has a variety of commands designed to help generate good time filters. The command edit is designed to set limits. The command gtgen is designed to generate good time intervals from those limits.

In addition to the concepts of monitors, limits and good times, there is the concept of day gaps . Even though a monitor may report on a regular bases, it may not report at all during extended periods of time. These times are considered day gaps and can be recognized by tabfilter in terms of the number of regular intervals the monitor did not report. This number can be set using the tabfilter command gap .

Below is a list of the valid tabfilter commands each with its own description.


display <monitor_name>

Display plots the named monitor against the time column of the corresponding ST table. In those cases where the number of rows of the ST table exceeds what can be displayed by the graphics device, a sampling of the data is plotted representing every N'th point of the real data. Up to four monitors may be displayed at any one time with repeated calls to display.

hide <monitor_name>

Removes the specified monitor from the display. If the monitor name is given as all , the screen will be cleared of all monitors.

mode <imode>

Mode changes the input mode to either line , for typing commands in a text window or gcur for using the cursor in a graphics display. In gcur mode, each command is executed as a colon command. For example, :mode line would return the input mode back to the text window.

list <table_name>

Lists the column names of the named ST table.


Window is an interactive command allowing the user to resize the selected window. As an interactive command, the window command must be quit by issuing a q command. This returns the user to the current input mode. When more then one window is displayed, a window must be selected by placing the graphics cursor over the desired window and pressing a key or mouse button. All subsequent window commands will be directed toward the selected window. The following window commands are available.

	a     Autoscale x and y axes
    *   b     Set bottom edge of window
    *   c     Center window at cursor position
	d     Shift window down
    *   e     Expand window
	f     Flip x axis
	g     Flip y axis
    *   j     Set left edge of window
    *   k     Set right edge of window
	l     Shift window left
	m     Autoscale x axis
	n     Autoscale y axis
    *   p     Pan x and y axes about cursor
	r     Shift window right
    *   t     Set top edge of window
        q     quit
	u     Shift window up
    *   y     Zoom y axis about cursor
    *   z     Zoom x and y axes about cursor

* Uses the cursor position at the time the command is issued.

gap <gap_number>

Gap sets the allowed integer number of missing nominal time intervals before considering the gap in reported data as a day gap. A nominal time interval is defined for each table from the difference of the first two values of the time column unless specified in the ST table by the header keyword DELTIME . In either case, a day gap is an extended period of time in which no information is reported. Setting the gap number allows the user to define what is meant by an extended period of time. Day gaps are identified in plotted monitors as gaps between connected line segments. Day gaps are also excluded time intervals in the generation of good time filters.

edit <monitor_name>

Edits the specified monitor's limits. Once this command is given, tabfilter enters gcur mode and waits for two graphics cursor entries, for the new upper and lower limits. The limits may be entered in either order. Both cursor commands and/or colon commands of the form:

:y limit_value

are excepted. The cursor x-position is not used. Any combination of the two entry methods is allowed.

delete <monitor_name>

Deletes a monitor's limits. However, if gtgen was previously executed, the previously computed good times still exist. In order to remove the good times produced by with these limits, gtnew should be executed.

limsave <table>

Saves the current limits in an ST table which consists of three columns, name, low and high. The name column holds the monitor name, low holds the low limit value and high the high limit value.

limload <table>

Loads an existing ST table containing limits that is of the same format as those produced by the limsave command.

showlim <monitor>

Show the limit markers of the displayed monitor.

hidelim <monitor>

Hide the limit markers of the displayed monitor.


Clears the list of good times intervals.


Generates good time intervals. For each monitor for which limits have been defined, gtgen generates a set of good time intervals. The set of good time intervals are defined by start and end times where the values of the monitor are within the set limits. Each value in the current column is tested to be within the defined limits. If two successive values go from being outside the limits to within the limits, the time of the second value defines a start time of a new good time interval. On the other hand, if two successive values go from being within the limits to outside the limits, then the time of the first value defines the end time of the current good time interval.

Once this set of intervals is defined, the intersection between this set and the compliment of the set of day gap intervals is taken. The day gap intervals are defined using the time difference between two consecutive times. If the difference is greater then the nominal time interval multiplied by the number of allowed gaps set by the command gap , the two times are considered the beginning and ending times for a day gap.

The interval set for each monitor is then intersected with each other to produce a single set of good time intervals.

gtsave <table>

Save internally stored good time intervals to an ST table. The ST table has a start time column, stime and an end time column, etime . Each row consists of a single good time interval.

gtload <table>

Loads an ST table containing good time intervals of the same format as those saved by gtsave .

filter <qpoe_file> <filter_name>

Stores a filter in the named qpoe file under the filter name. The filter is stored as a qpoe macro of the form (1023.34:1090.60, 2178.43:2218.75). One restriction made by qpoe is the length of the macro can be no longer then 8192. Therefore, if the macro is greater then this length, tabfilter will not create the filter and will print a warning message to the user.


Clears the screen.

help <command>

Produces a short help message on the specified command. If no command name is given, prints a short summary of all commands.


Repeated calls to display will display more then one plot, each in its own window.

Gtgen stores the resulting good time intervals within memory which may slow down the performance of tabfilter. Once the set of good time intervals have served their usefulness, the use of gtnew will elevate the pressure on the memory.

For each execution of gtgen , the intersection is taken between the resulting set good time intervals and the previously generated or loaded set of good time intervals. If no good time intervals have been loaded with gtload , it is to the users advantage clear any previously generated set of good times generated with gtgen with a call to gtnew .


This task displays the ST tables in a graphical form and therefore the example that follows is very basic. The user is strongly encouraged to simply experiment with the task in order to learn how to use it.

1. Display EUV ST tables using the tabfilter. The ST tables (1-7) are in the current working directory and there is no limits table:

    eu> tabfilter tables=tables[1-7].tab


dqselect, splot

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