Launch VLCj using Java Web Start

Launch VLCj by simply clicking on the above link. If the application is not present on your computer, Java Web Start automatically downloads all necessary files. Web Start is shipped with Sun's most recent release of the Java Runtime Environment (JRE 1.4.2). Click HERE to download the latest version of the JRE.

VLCj, the VLBA monitoring system client, is a JAVA program that works in conjunction with the program called VLS running on the computer Jansky at the Array Operations Center in Socorro. VLS, the VLBA monitoring system server, does all of the hard work of watching the monitor data coming from the VLBA antennas, massaging that data into a readable form, maintaining database files that keep a small amount of historical data for many of the monitor data points, and handles requests for data from client programs such as VLCj. VLCj's job is to connect to VLS and display the data maintained by VLS as the user wishes. VLS is designed to be a general purpose information server. It is written in the C programming language and is tailored to run on a Sun Microsystems UNIX box. Client programs using VLS may be written in any computer language. Currently there is a C version of VLC that is used for server testing, the real-time weather page for the VLBA sites that uses a CGI script which talks to VLS to get the weather information, and VLCj.

VLCj is written in the computer programming language JAVA (that's what the "j" means) as an application and was originally inspired by the OVRO Caltech Millimeter Array telescope realtime display program that is also written in JAVA as an applet (very clever!). Theoretically, since it is in JAVA, it should be able to run on any computer that has a JAVA Virtual Machine (JVM) installed.

VLCj supports graphing of historical data for many of the data items. When a display, for example the Weather display, is brought up the cursor will change to a hand when it is over an item that can be graphed. Clicking on a data item will select or de-select it. When the desired items to graph have been selected go to the Graph menu item and select the age the graph should have. Once the graph has been displayed it can be further manipulated from its own control panel. See Help on the Graph display for more information. VLS maintains the last 2000 points of data for each item that can be graphed.

Things you may not find explained anywhere else.

• The Sun symbol - This shows up on various displays.
  • * (yellow) - means the Sun is above the horizon
  • * (red) - means the Sun is 0 to -6 degrees below the horizon (civil twilight)
  • * (white) - means that the Sun is -6 to -12 degrees below the horizon (nautical twilight)
  • * (dark blue) - means that the Sun is -12 to -18 degrees below the horizon (astronomical twilight)
  • (no symbol) - means it's dark.

• The Moon symbol
  • ) - means that the Moon is waxing (getting larger)
  • ( - means that the Moon is waning (getting smaller)

• Colors - VLS assigns and VLCj displays data values and messages using 8 different colors. This outlines the general rules applied to the use of them:
  • (white) - used when conditions are "normal"
  • (bright white) - used when the outside temperature falls below 0 degrees Celsius (Baby It's Cold Outside!) and there could be a buildup of ice.
  • Aqua or Cyan - used when a condition or data value is "not quite right", when a temperature is too cold, or just to draw attention to a situation where something is happening.
  • Navy or Dark blue - used to indicate that the validity of a reading may be suspect usually due to some equipment fault.
  • Lime or Green - usually used to indicate that something is "going".
  • Yellow - indicates a warning regarding the data value or the flag. These conditions indicate that something is wrong, but that the astronomical data is probably not being affected.
  • Red - an indication that something is seriously wrong and that the astronomical data is probably being corrupted, and when a temperature is too hot.
  • Fuchsia or Magenta - indicates that a condition exists where possible equipment damage is ocurring, or the data value reported by the antenna equipment is unbelievably out of range.

The Startup display is where the VLCj program begins. It displays a bit of shameless advertising for the program and presents two menu items to select from: File and Help.

To start the program select File|Connect. The program will then try to establish a connection with the server program VLS on Jansky.

Under Help is "VLCj help" which is some general information and instructions about the program, "Help" which is this help item, "What's new" which will explain any new or removed features associated with this update of the program, and "About" which displays information about the program and information about the internet connection (it shows more information once a connection to the server has been established).

The Preferences panel allows you to change various program parameters. The data maintained by the Preferences panel is kept in the Settings sub-directory in the file Preferences.ini. The following is a list of the items that can be changed from the panel.

• Enable auto connection - This causes the program to display the Startup window in the middle of the display for about three seconds and then connect to VLS just as if File|Connect were selected from the Startup display menu. If you have started the program, then enabled this feature you must restart the program for it to take effect.
• Enable alarm clock bell - When the time reaches the setting for one of the alarms in the Alarm Clock display a dialog box will appear and an audible alarm will sound every second until the alarm is acknowledged. Unchecking this item's check box will disable the audible alarm.
• Enable Operator's "Check the displays" alarm - When the VL display is in use a dialog box will appear along with an audible alarm to remind the Operator to check through the displays at :15 and :45 minutes past the hour. Unchecking this item's check box will disable this notification.
• Enable incoming tech message notification - If the Tech Messages display is up a dialog box will be displayed and an audible alarm will sound when a tech message from one of the antenna locations or the Array Operations Center is detected and this box checked. Unchecking this item's check box will disable this notification. The notification rules will be set by the contents of the following two fields:
  • Notify on messages sent from - This field will normally be used by the AOC. This is where a comma-separated list of antenna location codes should be placed (SC,HN,NL...). Nornally all locations will be placed here for the AOC. When a message is sent and arrives from one of those locations then a notification will appear.
  • Notify on messages addressed to - This field will normally be used by locations other than the AOC. This is where a comma-separated list of antenna location codes should be placed (SC,HN,NL...). Normally only one location code will be placed here: the code for the local antenna location. When a message is sent by the operators it contains a list of locations it was sent to ("->snlpb" - the list at the end of a message). If the location(s) in this field matches one of the locations in the message's "->" list then a notification will appear.
• Terminal program - The path and name of a terminal emulation program may be placed in this field which will be started when "Terminal" is selected from the Tools menu.
• Default font size - This will set the font size used by the program when displays or tools are started from the Console display which is where the first display or tool must be started from. (Other displays always inherit their font size from the display they were started from.)
• Enable debug mode (for testing) - Turns various things inside the program on and off to aid in troubleshooting network, program, and server problems. Should normally be off since some troubleshooting routines may cause the program to stop when something happens -- just like bugs do.

The Console display shows the general status of the program once an attempt to connect to the server has been made.

The display contains the following fields:

• Status - shows the status of the TCP/IP socket connection between VLCj and the server VLS running on the computer Jansky. The following messages may appear in the status field:

• Not conected - This will be displayed before any attempt to connect has been made.
• Disconnected - the state of the connection before the connection is established, after the connection to the server has been lost, or the connection has been terminated with the File|Disconnect menu command.
• Connecting... - displayed after the File|Connect menu command has been selected, but before the server connection has been established.
• Negotiating... - this is displayed after the TCP/IP connection has been made, but before the "handshaking" between VLCj and VLS has been completed.
• Connected - the normal status for the connection.

• Sentences - Data transmitted between VLCj and VLS is handled using sentences. One sentence may contain one location's weather temperature value, a line of data in the Log display, or one checker message. This field shows the number of sentences that have been sent from VLS to VLCj. It should increment at least 30 sentences per minute if everything is okay.
• Displays - there is a limit of 30 displays up at a time. This field simply indicates how many of them there are.

The Graph display is used to present a graphical representation of historical data. The items graphed are selected from the other data displays, and the oldest age of the data is determined by the Graph menu selection. The initial set of data is requested and downloaded from the server when the display is started. Once this data set has completed the transfer from the server several fields are filled in and the graph is drawn. Following this the display may be manipulated to produce variations in the graphs of the original item or items.

MultiGraphing

It is possible to graph items on the same graph that do not appear on the same display such as any of the cryo system readings from the Cryo Systems display and the outside air temperature on the Weather display. To do this bring up the two (or more) displays that contain the items that you want to graph. Select on each of the displays the items you want included in the graph. Go to the Graph menu item on any of the displays you are working with and select "Plus other displays", then return to the Graph menu and select the age for the graph as you normally would. To graph the selected items from only one display (the default) go to the Graph menu item and ensure that "This display only" is selected.

The Graph display contains the 'control panel' on the left and the graphing area on the right. The control panel contains several fields, checkboxes, and buttons.

• Items - This section contains ten fields which show the data items being graphed. The codes in these fields are how VLCj identifies to VLS what data items are to be sent. They are always in the form "<Tag>;<Loc>". The first letter will usually always be "M". The next two letters identify the general group the data belongs to, such as "RC" for receivers, "WX" for weather, "HE" for Helium systems, "EN" for environmental data, etc. The rest of the letters identify the item. They are somewhat cryptic, but generally try to spell out what the item is. Some examples: MWXTP - weather temperature, MHERA - Helium return pressure (compressor A), MENVRMV - vertex room refrigerant modulation valve control voltage. Letters following the semi-colon indicate the location code where the data is from. Most of these are the two letter VLBA site codes, but another code that may show up is "SVR". This indicates that this data is generated and maintained by the server. The color of the text in the field corresponds to the color of the graph for that item.
• Hide/show graph checkboxes - Unchecking the leftmost checkboxes to the left of the Items fields will prevent that item's graph from being displayed. This can be used to unclutter a graph.
• Lines/points graph buttons - Checking the radiobuttons between the hide/show checkboxes and the Items fields will cause the graph for that item to be drawn using points instead of lines.
• Offset value fields - A value placed in this field will be added to (or subtracted from if negative) the Y-axis value of all of the points of the associated graph item.
• Refresh - This button causes the display to re-request a fresh set of data using current T-max and T-min values.
• T-max - This is the age in hours of the oldest data that will be displayed on the graph. Press the Enter key to cause the graph to be redrawn after changing this field.
• TMOrig - Returns the T-max value to its original value.
• T-min - This is the age in hours of the youngest data that will be displayed on the graph. Press the Enter key to cause the graph to be redrawn after changing this field.
• TmOrig - Returns the T-min value to its original value.

When a display is first started T-max will correspond to the age of the Graph menu item requested. T-min will always be 0.00 indicating that data from T-max up to the most recent data avalible was sent by VLS. Once the graph has been started these numbers may be changed as desired.

• Re-range - The display calculates the Y-max and Y-min values when the data is initially loaded. This calculation may be redone at any time by using this button. This button would be used, for example, after a graph is hidden or shown using the hide/show graph checkboxes. The Y-max and Y-min values are recalculated using the data points of the graph being displayed.
• Y-max - This is the maximum Y-axis value for the graph. Press the Enter key to cause the graph to be redrawn after changing this field.
• YMOrig - Returns the Y-max value to its original value.
• Y-min - This is the minimum Y-axis value for the graph. Press the Enter key to cause the graph to be redrawn after changing this field.
• YmOrig - Returns the Y-min value to its original value.
• Lock Y-axis - prevents the Y-max and Y-min values from being recalculated during a refresh (see below).

As the initial set of data is sent VLCj keeps track of the maximum and minimum values of all of the data. Once all of the data has been received VLCj adds 1.00 to the maximum value, and subtracts 1.00 from the minimum value. These become the initial Y-max and Y-min values. This is done to keep, for example, a nearly straight graph from being drawn pushed up against the top or bottom edges of the graph. This calculation is repeated each time a set of data is requested from the server. If the Y-max and Y-min values are manually changed, and then a new set of data is requested from the server then the manually changed values will be replaced with newly calculated ones. To prevent this from happening the "Lock Y-axis" checkbox can be checked to freeze the manually entered values prior to requesting a new set of data.

What is the difference between refreshing and redrawing? Redrawing is when the graph is redrawn using the currently downloaded data and the values in the T-max, T-min, Y-max, and Y-min fields. This occurs anytime the values in these fields are changed and the Enter key pressed. Refreshing will cause the program to re-download all of the data during the age range specified by the T-max and T-min fields.

• Clicking on the graph - normal click - Clicking on the graph will draw a set of crosshairs, leave a small square at the point of the click, and display the corresponding T-axis (date/time) and Y-axis value below the graph. The date/time will initially be in UT time. This is indicated by the "UT" displayed in the upper left hand corner of the graph area. The date/time displayed may be displayed in the local timezone for any of the locations that the graph is displaying data for by clicking on any of the fields in the Items section. For example, if one of the items being graphed is MWXTP;LA, clicking on the field with "MWXTP;LA" in it will change the timezone indicator in the upper left hand corner of the graph to "LA" (Los Alamos) and cause any date/times displayed by subsequent clicks on the graph to be converted to the MST/MDT timezone. Clicking anywhere in the graph area outside of the graph proper will reset the timezone setting to UT.
• Clicking on the graph - "right" click (Y-axis markers) - Right clicking on the graph will draw a small red box at the point of the click, draw a line to the left edge of the graph, and display the corresponding Y-axis value. Up to ten markers may be set. Right clicking anywhere in the graph area outside of the graph proper will erase all of the markers.
• TOD - Time of Data. This is the UT time that the current set of data was requested. This will change each time the data set is refreshed.
• That number in the lower right hand corner - This is the average number of data points in all of the downloaded data.

Every 20 seconds the station computers at each site go through a list of all of the site and antenna equipment looking for voltages, pressures, and currents that are out of range, and items that are out of position. When an out of specification condition is found a "checker message" is generated. The current list of items that the station computers think are out of spec are shown by this display.

Buttons on the toolbar

• Location buttons - A button is provided for each antenna location. If the station computer observing system is running (an observing schedule file has been loaded) then the button for that location will be green. If the observing system is "idle" then the button will be red. Depressing any of these toggle buttons will cause any checker messages for that location to be displayed.
• All - Pushing this button will select all of the antenna locations.
• Obs - This button will select all of the antenna locations that are currently observing.
• Idle - This button will select all of the antenna locations that are currently idle.
• Clear - This will untoggle all of the currently depressed location buttons.
• E>W - This will step through the antenna locations in east to west order. If one location is already selected then the stepping will begin there, otherwise the sequence will begin with the easternmost location.
• W>E - The will step through in west to east order.
• Priority buttons - The checker messages are assigned one of five priority levels based on the severity of the condition described by the message. These toggle buttons may be used to filter out messages of the different priority levels. This priority level system is an ancestor of the system originally used at the VLA where the number of the priority level corresponded to the number of "stars" (asterisks) that were printed with each message on the VLA Control Room LA-120 line printer. The use of asterisks is still used in VLCj's Log display.
  • 4 - These are the highest priority. These indicate that something is seriously wrong and that equipment damage may be ocurring.
  • 3 - These messages indicate conditions where the astronomical data could be affected by the indicated condition.
  • 2 - These messages indicate that the piece of equipment or signal level is out of spec and should be adjusted at the next available opportunity, but the level of severity is not high enough to cause the astronomical data to be corrupted.
  • 1 - These are low level messages that usually indicate transient conditions or equipment that needs to be looked at "someday".
  • 0 (white) - messages that can probably be ignored.

The Tsys display reports the current system temperature readings for each observing baseband channel. The information updates any time a "group" of BBC total powers and switched powers are processed (about every minute), and when a "power" record is processed (determined by the observing file -- usually about every two minutes, and at the end of scans).

The color attributes for the data are set according to the normal range for the current observing wavelength band and will be white when everything is normal. If the Tsys level is 10% lower than it should be the data will be displayed in aqua or cyan. If the level is 10-50% above normal it will be displayed in yellow, 50-100% in red, and greater than 100% above normal in fuchsia or magenta.

Any channel's data may be graphed on the Graph display. No separation is made for observing bands, so the graphs for multi-band, short-scan projects may be a bit confusing. The graph points will only be derived from the power record data.

Only channels 1, 2, 4, 8 and 16 (they have a "." following the channel label) may be selected for monitoring on the Monitor display. This is because VLS only sends out realtime data for the purpose of graphing for those channels. In addition, this data is only sent out by VLS when a power record is sent by the station computer, and processed by VLS whose averaging time is greater than 100 seconds. The limited number of channels, and the minimum averaging time is done to prevent swamping clients with data during high-channel/short-scan time projects.

The Cals display reports the current cable cal (500MHz round trip phase) measurement, and when observing it indicates the Pcal extractor setups for the first eight baseband channels.

A three-letter code will appear for each channel to which a Pcal extractor is assigned. The three letters indicate the front end letter band (X=4cm, S=13cm, etc.), the polarization, and the baseband converter sideband. If there is no code then no Pcal extractor is assigned to that channel. Page 1 indicates the setups for extractors measuring the amplitude of the Pcal signal, page 2 the setups for extractors measuring the Pcal signal phase, and page 3 the setups for extractors involved in state counting.

Any channel's data may be graphed on the Graph display. No separation is made for observing bands, so the graphs for multi-band, short-scan projects may be a bit confusing.

Only channels 1, 2, 4, and 8 (they have a "." following the channel label) may be selected for monitoring on the Monitor display. This is because VLS only sends out realtime data for the purpose of graphing for those channels. In addition, only one "point" of data is sent per channel (the extractors can be configured to monitor several tones per channel). The limited number of channels, and the limited number of points are done to prevent swamping clients with data during high-channel/short-scan time projects.

This display allows up to ten alarms to be set. The alarms must be set in UT time. The display must be kept visible or at least minimized or the alarms will not go off.

The left field on each line is where the UT date and time is entered. The long field on the right may contain a text message that will be displayed when the alarm goes off.

Entering the date/time:

A "date", a space, and a "time" must be entered.

One or more letter D's may be entered for the date. One "D" indicates that the date setting of the alarm should be the same as the current UT date. Two D's (like "DD") indicates that the date setting should be the current UT date plus one day. If the actual date is entered then it must be entered in the yyyyMMMdd format like 1999DEC05.

The time may be entered as "5" for 05:00, "13" for 13:00, "2346" for 23:46, or "16:34" for 16:34. No checking is done so you may enter "27:89" if you want to, but then the alarm will never go off.

The Converter display takes your input and displays the value converted to other units.

The display will convert between the following unit systems:

• Degrees Celsius (C)

• Degrees Fahrenheit (F)

• Degrees Rankine (R)

• Degrees Kelvin (K)

• Miles per hour (MPH)

• Kilometers per hour (KPH)

• Meters per second (M/S)

Enter values to be converted into the field in the display followed by the units system identifier. For example

34.5mph
8m/s

When finished press the Enter key. The conversions will be displayed in the area below the field.

The possible identifiers for the units that are recognized by the display are listed in the parentheses following the system names above.

This is a display of small graphs which update in real-time. Items to be monitored are added to the display by selecting them in the regular data displays (like the Weather display or the Cryo Systems display), and then selecting "Monitor" from the Graph menu.

When a point is selected for monitoring its graph appears with the normal VLS/VLC ID code in the upper left hand corner of the graph, a graph of the last 25 data points (if available), the UT time of the last data point in the lower left hand corner, and the value (pressure, voltage, etc.) reading of the last point in the graph. The color of the graph points and the data value will change to match the color attributes currently assigned to the value and the attributes that the data had when originally recorded. The graph, the UT time, and the value will update as new data is sent from VLS. Most monitor points only update every few minutes, others only once or twice per hour. Data values that do not change from one reading to the next will not be sent by VLS which can make the graphs appear as though they are not updating. Fresh data for all of the graphs can be obtained by selecting the Refresh item in the File menu.

An item's graph is removed from the display by selecting its VLS/VLC ID code from the list of codes under the Close menu.

The display attempts to rearrange the layout of the window as graphs are added and closed. Selecting/reselecting the font size from the Font menu will redraw the display to accommodate all of the graphs currently contained in the display, if possible.

There is a limit of 50 graphs being displayed at one time.

The RCMD display is the control panel for the array. All buttons and functions appear available to everyone, but for commands generated by this display to actually function requires that permissions be granted on the server VLS.

The display is split into four sections: Command/Readback, Locations, Arguments, and Commands.

The Command/Readback portion of the display shows the constructed command line sent to VLS to execute a command, and the responses sent from the station computers.

This display shows a list of the current VLC and other program clients connected to the VLS server.

This display does not update automatically. You must use the Refresh button to obtain fresh client data.

Explanation of the columns:

• N - this is just an ordinal number of the clients (1,2,3...)
• ID - the ID number that is associated with each client in VLS. This number will not change as long as the client stays connected.
• Hostaddr - the IP address of the host machine.
• Hostname - the name assigned to the above IP address by VLS.
• Username - the account name provided by the machine that VLC is running on.
• Time connected - the UT date/time that the client connected.
• Type - the connection type: Long, Short, or Mid. Long connections are normal for client programs like VLCj where new data is sent to the client automatically, and the client can make requests for data. Short connections are typically used by web pages. The web page software connects, requests/retrieves some data, and then VLS closes the connection. Mid connections allow client programs to connect to the server, request some data, but then stay connected to make further requests. No data is automatically sent.
• Program - the name of the program the user is connected to the server with.
• Version - the version number of the user's program.

This display shows a line of data related to the current condition of the server and columns of numbers which indicate the number of monitor data records of each type that have been sent by the station computers to the array control computer Jansky.

This data is not normally transmitted by VLS, so the Refresh button must be used to obtain up-to-date counts. The Server field will automatically update every five minutes.

• Server - this line updates every five minutes and shows the number of server cycles ("cy") that VLS has gone through since it was started (each cycle is about .5 seconds long), the number of clients ("cl") that were connected at the indicated UT time, the number of "active" checker messages ("ck") for all of the locations at the indicated time, the maximum number of bytes of data ("mx") that was sent to the clients in any one server cycle during the previous five minute period, and the average ("av") number of bytes per second that were sent to a client during the previous five minute period.
• Ctrl1 - the number of Control 1 records. These records are normally sent at each scan change.
• Flag - the number of Flager records. These are on/off bits that indicate conditions such as synthesizers in/out of lock, the sub-reflector in/out of position, etc.
• Mon1 - the number of Monitor 1 records.
• Mon2 - the number of Monitor 2 records. These records contain the periodically sampled data from various pieces of equipment.
• Chk1 - the number of Checker 1 records. These are sent by the station computers when an out of specification condition is found by the checker message system.
• Chk2 - the number of Checker 2 records. These are sent when the checker message system detects that an out of specification system condition has cleared.
• Pcalx - the number of Pcal Extractor data records. These are sent periodically by the observing system as specified in the observing file.
• Pwr - the number of Power records. These records contain the BBC total and switched power level readings for calculation of the system temperature value (Tsys) for each channel.
• Cmnt - the number of Comment records.
• Tape - the number of Tape Drive Information records.
• Wea - the number of Weather Data records.
• Test - the number of Test Data records. These are results from any of the Startup tests such as BBC Lock Test, and the Focus and Rotation tests.
• Other - the number of other, unspecified record types.
• Bad - the number of bytes of monitor data skipped because the data was thought by VLS to be unreadable.
• Short - The monitor data records all have a common header of data and then a body of data that varies according to the data type. The length of the body is contained in the header. If a record header is read, but all of the body of the record can not be read then this counter is incremented.

All counters are cleared at UT midnight.

The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.