Data Acquisition System

Data Viewer User Guide

• Getting Started
• Changing Signals
• Adjusting/Saving Settings
• Display Mode
  • Stop
  • Pause
  • Real-time Data
  • Off-line Data
    • Time Settings for Playback
    • PlayFwd
    • PlayBack
• Long Playback
• Display Option
  • Time Sequence
  • Spectrum
  • Trend
  • A/B Display
  • Freq vs Time
  • Diag
• Display Method
  • Standard
  • Multiple
  • Persistence
  • Stack
• Other Display Options
  • Total Channels
  • Resolution
  • Refresh Rate
  • Y Scale Type
  • Selected Signal On/Off
  • Color Selection
• Trigger
• Printing
• Quit/Exit
• Other Tips
  • Some useful Xmgr Tips
  • Status Report/Debugging Information
  • Troubleshooting

Getting Started

Working directory: this version of the data viewer is at

2. click Realtime. By default, 16 channels will be displayed in real-time mode on the Xmgr window. Note: some graphs may look blank, which means Y-Axis settings need to be adjusted (see the topic Adjusting/Saving Settings below).

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Changing Signals

To change the signal for a particular channel, first get the Signal Selection window by clicking Sig Select on the top panel. The area under Group Names shows all of the current available groups. Clicking on any group name, the Signal Names will show the list of signal names inside the group. Select the desired signal. Then select the channel number by entering the number at the New signal selected for Ch. field or choosing the channel number from the Ch.Sel. menu. Click Select to make the change.

All channels can also be changed at once by using Main->Restore Setup if there is a pre-saved file.

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Adjusting/Saving Settings

There are two types of X-Axis adjustments. If the X-Axis is in time sequence display (in seconds), make a selection from the pull-down menu X Axis on the top panel. The maximum is 16 seconds and the default is set to 8. If it is in frequency display (Hertz), it can be adjusted by typing numbers in the Min and Max fields for the Freq. Range (the maximum range is from 0 to 8192). Any X-Axis adjustment affects all channels.

Y-Axis scale is adjustable for each channel while in time sequence display. First select the channel from the channel select panel, then hand type the range in the Y Scale Min and Max text fields. It will affect all channels while in frequency display.

Different types of Y Scale are also available. See Y Scale Type for details.

Usage of AUTO Setting: notice that there is an item AUTO under the pull-down menu Y Axis. By selecting AUTO, Xmgr will automatically set the proper display Y-range for the selected channel. However it is not recommended to use auto setting for the general display since it may slow down the display. AUTO should be used only for locating the curve and then Y-Axis scale should be set manually. Do not use AUTO for more than two channels at the same time.

Once all settings are adjusted, you may save them to a file for later recalls. To save, use Main->Save Setup; to restore, use Main->Restore Setup from the top panel.

Note: all fields on the control with lighter color accept hand typing (you have to type Enter after typing your entry); entries at the fields with darker color can only be changed by using the corresponding pull-down menu(s).

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Display Mode

Stop: While in Stop, the Xmgr display is in an interactive mode. You may use any Xmgr menu or buttons. For the usage of Xmgr, see Xmgr User Guide.

Pause: This feature is designed for trend data display only. Pressing Pause will stop the display while the real-time trend data being recorded. To resume, select Realtime. For non-trend display it works as same as Stop.

Real-time Data: If Realtime is selected, data is displayed in a real-time mode, with maybe a 1-2 second delay from the time it is actually acquired. The display is in general updated once per second; and for certain cases it could be updated up to 16 per second (see later topic Refresh Rate for more details).

Off-line Data: Along with real-time data display, data stored by the Data Server may also be recalled for presentation in Xmgr.

Time Settings for Playback:

reference time: time for starting (in PlayFwd) or ending (in PlayBack or Long Playback) the display. To set it, enter the year, month, day, hour, minute, and second into the fields at the first row of Time Settings. To quickly set all fields to the current time, simply click TimeNow.

display period: the length of time period for playback. Enter the days, hours, minutes, and seconds into the fields at the second row.
(make sure to press Enter after each entry.)

example:

reference time: 98:10:21:14:55:05

display period: 0:0:15:0

PlayFwd: The Xmgr will display data starting from the reference time. It will last for the length of the display period, with refreshing for each second increment. e.g. in the above setting, it will display from 14:55:05 until 15:10:04.

PlayBack: The Xmgr will display data of the display period and end by the reference time. Therefore in the above example, it will start from 14:40:05 and play until 14:55:04, refreshing for each second increment.

Long Playback

Long Playback is designed for displaying off-line data for a longer period of time. It produces one or more new Xmgr window(s) and displays all information for the given display period at once. Note: It will not start the display until all of the data information has been read. Thus longer display period and more channels request longer loading time.

To use Long Playback, first set the time period by the same method as in PlayBack. Click the Long Playback button which is located at the upper right corner of the main control. This will bring up the Long Playback control window. Up to 16 channels can be chosen from the left panel of the Long Playback control.

Decimation: Data decimation can be chosen as full data, second trend, minute trend, 10-minute trend, or hour trend. The default is set as the following:

Decimation	Display Period
full data	less than or equal to 10 seconds
second trend	between 10 seconds and 1 hour
minute trend	between 1 and 60 hours
10-minute trend	60 hours to 30 days
hour trend	more than 30 days

X-Axis Format: There are two types of X-Axis formats can be chosen for trend data display: The Date/Time choice will show X-Axis in yy-mm-dd hh:mm:ss format. And the Total Time shows the X-Axis in seconds (if the period is shorter than 60 minutes) or minutes.

Graph Mode: Standard displays selected channels in one Xmgr window, with each channel in a separated graph. Multiple display all selected channels in the same graph. Multiple Xmgr opens a new Xmgr window for each selected channel.

More Options: You may choose to show the maximum, minimum, or/and mean values. It will display Mean if none of them is chosen or if more than one is chosen for the multiple case. You may also choose to show or hide the X and Y Grid. You may also connect to a different server rather than the server which is used at the starting of the main control panel by typing the server IP and port number into the corresponding fields.

Display Option

Time Sequence: It displays data in time domain. The X-Axis shows time in seconds and Y-Axis is in ADC counts. Up to 16 seconds of data are plotted in each graph. The larger graph at the left upper corner will show the plots for the selected channel which can be changed from the channel select panel.

Note: The larger graph at the left upper corner can be turned on/off.

Spectrum: The larger graph at the left upper corner displays the power spectrum of the selected channel over a period of 1 second. The X-Axis is in Hertz and the maximum range may be set from 0 to 8192. Additional choices from the submenu are With Windowing which displays spectrum with a data windowing (Welch) or No Windowing.

Trend: Trend data can be viewed in real-time. You may choose from the submenu to display maximum value (Max), minimum value (Min), mean value (Mean), or all of the above three (All) for each channel.

Settings: The X-Axis shows the length of the time period (in seconds) of trend being displayed. It resets itself to zero every 12 hours (43200 seconds). While resetting, all Xmgr sets will be saved automatically to a .save file with the time stamp as its name. The settings of Y-Axis for trend display are taken from the TimeBase settings.

Note:
1. The real-time trend display can be paused by clicking Pause button from the Display Mode panel. Use Realtime to resume. Some data may get lost if paused for long time.
2.Trend playback can only be viewed by Long Playback.

A/B Display: This function provides the following 2-channel analysis features: the data plots (defalut) and the power spectra for both channels (Spectrum A, Spectrum B), correlation of the two channels (Correlation A/B), power spectrm of the time correlation (Spectrum A*B), and one channel against another (A vs B).

The signals and options for these features can be selected from the A/B Control panel. To get the panel, click the A/B Control button (as shown on the right).

Settings: The settings for the time base plots and spectra are taken from the general TimeBase and Spectrum settings. The ranges of axes for the time correlation are fixed: horizontal [-0.5, 0.5] and vertical [-1, 1]. Changing them can only be done by mouse in the Xmgr window.

Freq vs Time: Frequency vs Time mode demonstrates spectrum history for the selected channel. Carpet or Waterfall options may be chosen from F.vsT. Control panel. (click the F.vsT. Control button to get the panel.)

The carpet mode is based on Keith Riles's code which is modelled after Bruce Allen's diag example program in GRASP. The carpet plot has time history as its horizontal axis with the latest time at the right. The vertical axis is in frequency. Pixels are shown for each frequency channel in which the power exceeds a certain threshold. As time progresses, the pixels move toward the left in a roll mode like that used for time series display. There are two types of thresholds described below. History shows back to the last 30 (by default), 60, 90, or 120 seconds. No threshold checking is performed until 10 seconds of data have been taken.

Carpet w/Absolute Threshold: the threshold is a constant specified (in db) by a text field on the F.vsT. Control panel.

Carpet w/Variable Threshold: the threshold depends on both the mean value and the typical deviations seen for the channel. One may specify the threshold on a text field of the F.vsT. Control panel which is in units of "sigma". Instead of a true RMS, however, what is used is the running average of the absolute deviation of the channel from its own running average. The averaging is done via an exponential decay time weighting (time constant = 10 seconds), similar to that used in the diag program. Ideally, the variable-threshold carpet plot should appear to be a radom distribution of dots. Non-randomness, such as clustering, horizontal lines, or vertical lines, indicates transient noise sources (or signal).

Waterfall: waterfall shows the history of the power spectrum of the selected channel. The left graph shows up to 30 (by default) spectra simultaneously, corresponding to spectra observed at earlier times. The bottom curve is the current spectrum. The one above it is the preceding one. Again, as for the carpet plot, one looks for non-random behavior to recognize transient noise or signal.

Settings: For changing the frequency range of spectra, use the Freq. Range Min and Max text fields on the main control panel. Other choices can be seen at the F.vsT. Control panel. Also, different colors for display can be selected from the Color Selection. (try multiple and have fun!)

Diag: The Diag option allows users to perform certain arithmetic operations (+, -, *, /) on chosen signals. The Diag Control panel can be obtained by clicking the Diag Control button (as shown on the right).

This function takes four signals (called Ch. A, B, C, and D) as its inputs (level 1). Operations can be performed on Ch.A and Ch.B, Ch.C and Ch.D respectively (level 2). One more layer of operations (level 3) can be applied to the two signals on the level 2.

Display Method

The display methods described here don't apply to A/B Display, Freq vs Time, or Diag option.

Standard displays up to 17 graphs. The larger graph at the upper left corner shows the plot for the selected channel and option. Other graphs show up to 16 channels of data in time series, with channel number 1 at the lower left and increasing to the upper right.

Note: the larger graph at the upper left corner can be turned on/off by checking/unchecking the Selected Sig. box.

Multiple displays up to 16 channels in the same graph. The Y-range is the union of Y-ranges of all shown channels. This method doesn't apply to Trend, but does apply to Trend.max, Trend.min and Trend.mean.

Persistence displays the selected channel for the last 4 seconds. The curves fade away with time passing. Apply to TimeBase and Spectrum only.

Stack displays the selected channel for the last 4 seconds. The curves shift toward the upper right with time passing. Apply to TimeBase and Spectrum only.

Other Display Options

Total Channels: It is the number of the channels to be displayed. It's used for Standard or Multiple mode. The default is set to 16. To adjust this number, use the pull down menu Display->Total No. of Channels from the top panel.

Resolution: The resolution of the time sequence data display is adjustable by using the pull down menu Display->Resolution. Each channel will be displayed at the chosen resolution or the data sampling rate of the signal, whatever is smaller. The default is 128 Hertz and the maximum is 16384.

Note: In order to keep up the display speed, an limit is set for the number of points appeared in a graph. Thus choosing higher resolution may result in reducing the total display time (X-Axis range). Here is the chart:

Resolution	Maximum Time
128	16 sec
256	8 sec
512	4 sec
1024	2 sec
2048 above	1 sec

Refresh Rate: In general, the refresh rate for graphing is once per second. It is adjustable up to 16 times per second for Standard or Multiple mode in TimeBase by using the pull down menu Display->Refresh Rate.

Y Scale Type: Four types of Y-Axis scale for each channel are available: Linear, Exp, Log, or Ln. The default is Linear. To change Y scale type for a particular channel, first select the channel number from the channel select panel, then use the pull down menu Y Axis->Y Scale Type to select the scale type.

Selected Signal On/Off: There is a check box next to Selected Sig. (shown in the picture). This gives an option to turn on/off the large graph at the upper left corner which shows the selected channel in standard display.

Color Selection: There are 6 choices under the color selection: green, white, red, blue, yellow, and multiple. The selected color is used for persistence or stack display, as well as the A/B display and Freq vs Time mode. The multiple color is only used for Freq vs Time/Waterfall case, in which the curves are displayed in different colors.

Trigger

Clicking the Trigger Control button which is located at the right side of the main control will bring up the trigger control window:

Printing

Print to printer: You may use the Print feature from Xmgr. First stop the display. Then click on File located at upper left corner of the Xmgr window. Choose Print from the pull-down menu and the picture will be sent to the default printer.

Print to ps file: Click the Print to File button located at the rightside of the main control. The current display will be saved as a .ps file with the time stamp as the file name, i.e., 99-9-15-18-24-19.ps . Note that you do not have to stop the display to use this feature.

Quit/Exit

Choosing Main->Quit Display from the top pannel will set the Xmgr window free from the Data Viewer Control. The Xmgr may be closed in the same manner of closing a X-term. The basic settings are saved and will be restored automatically when you start another new Xmgr display by Main->Start.

Choosing Main->Exit will exit the data viewer program. If you need to save the current settings, use Main->Save Setup befire exiting.

Other Tips

Some useful Xmgr Tips:

Note: Make sure the Xmgr is in an interactive mode (Stopped) before applying any of the followings.

• data status: Xmgr allows user to view data information for each graph. Click on the graph you want to look at. Then select Data->Status from the pull-down menu of the Xmgr window. A status window will pop up and the information such as X and Y maximum/minimum is displayed. This is a convenient way to find out the the proper display range. Thus Y-axis range can be set accordingly.
• save Xmgr file: the current plots can be saved as a Xmgr file and reopen by Xmgr. Use the pull-down menu File->Save as and type in a file name. To reopen, use File->Open.
• adjust scales: X and Y scales are adjustable from Xmgr directly. Use Plot->World scaling.

Status Report/Debugging Information: Status report and debugging information are shown at the terminal window where the Data Viewer Control is started. It shows the general display information, user's selections, warnings and error messages. While data being displayed, it shows the time stamp of the data and indicates any block drop as well. It is advised to check the message window whenever you experience something 'weird'.

Troubleshooting:

Note: Always check the status messages first. It may help you to target the problem sooner.

• problem: can not start the Data Viewer Control.
  possible cause: no data server is available.
  suggestion: make sure the server IP address is typed correctly and the server is running.
  
  
• problem: Xmgr display doesn't keep up the speed.
  suggestions:
  1. set smaller X-Axis range.
  2. do not use AUTO setting for display.
  3. display less channels, especially when higher refresh rate is used.
  4. reduce the resolution.
  5. reduce the refresh rate.
  6. while using A/B Display, turn off the unnecessary options.
  
  
• problem: unexpected Xmgr display interuption.
  possible causes:
  1. the display is triggered.
  2. playback is finished.
  3. the selected channel number is larger than the total channel number.
  4. try to display the correlation of two channels with different sampling rates.
  suggestions:
  1. see if the Trigger On box is checked and check the status report.
  2. if this is the case, a line 'trailer received' can be seen in the status report.
  3. select larger number for Total Channels; or move the signal to a channel with smaller channel number.
  4. this feature is not supported currently. Check the status message to see if this is the case.
  
  
• problem: no action being taken after a selection.
  possible causes:
  1. no Enter is typed after the entry.
  2. the connection between control and display is not established; this could be caused by a network error or by accidentally selecting Main->Quit Display.
  suggestions:
  1. note that all fields on the main control panel with lighter color accept hand typing, but you have to type Enter after typing your entry; entries at the fields with darker color can only be changed by using the corresponding pull-down menu(s).
  2. check the status messages on the message window. The line

  messg received *************************

  should appear after each selection. If not, quit the Xmgr display and start a new one.
  
  
• problem: X or Y-Axis settings can not be changed.
  possible cause: you are not alowed to make this change under the current display option.
  suggestions: if you need to adjust X or Y-Axis settings for any time sequence display, select TimeBase from the Display Option panel and make desired adjustments for the selected channel and then change back to your original display option. If the adjustment is for any frequency display, do it with Spectrum option.
  
  
• problem: graphs flash in Xmgr display.
  possible cause: two or more AUTO settings are being used.
  suggestion: manually set Y Axis and Y Offset for all channels. see the Usage of AUTO Setting under the topic Adjusting/Saving Settings.
  
  
• problem: Long Playback doesn't show all the data requested.
  possible cause: there is no enough data stored by the Data Server.