Guralp Systems Scream User Manual

Scream! 4.5

Seismic Monitoring Software

User guide

Part No. MAN-SWA-0001

Designed and manufactured by Güralp Systems Limited

3 Midas House, Calleva Park Aldermaston RG7 8EA England

Proprietary Notice: The information in this manual is proprietary to Güralp Systems Limited and may not be copied or distributed outside the approved recipient's organisation without the approval of Güralp Systems Limited. Güralp Systems Limited shall not be liable for technical or editorial errors or omissions made herein, nor for incidental or consequential damages resulting from the furnishing, performance, or usage of this material.

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Table of Contents

1 Introduction...............................................................................................................	6
1.1 Scream! as a real time application.....................................................................	6
1.1.1 Diagnostic features......................................................................................	7
1.1.2 Digitiser configuration................................................................................	7
1.1.3 Networking..................................................................................................	7
1.1.4 Recording and replay..................................................................................	7
1.2 Scream! as a data viewer....................................................................................	8

2 Installation and Configuration.................................................................................		9
2.1	Installation on Windows....................................................................................	9
2.2	Installation on Unix or Linux.............................................................................	9
2.2.1 Installation from an RPM or .deb................................................................		9
2.2.2 Installation from a .tar.gz archive...............................................................		9
2.3	Initial Configuration – all platforms................................................................	10

3 The main window...................................................................................................		11
3.1	Serial ports........................................................................................................	11
3.2	The stream buffer.............................................................................................	14
3.3	The source tree.................................................................................................	14
3.3.1 Icons...........................................................................................................		15
3.4	The stream list..................................................................................................	16
3.4.1 Sorting options..........................................................................................		18
3.5	The status bar...................................................................................................	19
3.6	Viewing streams...............................................................................................	19
3.7	Connecting to instruments...............................................................................	21
3.8	Calibration data................................................................................................	21
3.8.1 Examples....................................................................................................		25
3.9	Other features...................................................................................................	26

4 Waveview windows................................................................................................	27
4.1 Window functions............................................................................................	28
4.1.1 Zooming in and out...................................................................................	28
4.1.2 Making measurements..............................................................................	29
4.1.3 Printing......................................................................................................	30
4.1.4 Filtering.....................................................................................................	30
4.1.5 Paused mode..............................................................................................	31
4.1.6 Other icons................................................................................................	34
4.1.7 Context menu............................................................................................	35
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4.2	Stream functions..............................................................................................	36
4.2.1 Identifying streams....................................................................................		37
4.2.2 Changing the appearance of streams........................................................		37
4.2.3 Scaling streams..........................................................................................		38
4.2.4 Viewing offsets, ranges and averages........................................................		38
4.2.5 Spectrogram...............................................................................................		39
4.3	The Filter Design window................................................................................	40
4.3.1 Filter parameters.......................................................................................		41
4.3.2 Viewing spectra.........................................................................................		44
4.3.3 Display options..........................................................................................		46
4.3.4 Pre-sets.......................................................................................................		47
4.4	Display options.................................................................................................	48
4.4.1 Display set-up............................................................................................		48
4.4.2 Stream mapping........................................................................................		49
5 Networking..............................................................................................................		53
5.1	My Client..........................................................................................................	53
5.1.1 TCP clients.................................................................................................		55
5.1.2 Multicast clients........................................................................................		55
5.2	My Server..........................................................................................................	56
5.3	Server Buffer.....................................................................................................	59
5.4	Gap recovery.....................................................................................................	59
5.5	Retrieving data over dial-up links....................................................................	59
6 Supplementary windows........................................................................................		63
6.1	Terminal windows............................................................................................	63
6.1.1 Communicating with instruments............................................................		63
6.1.2 Macro commands......................................................................................		65
6.1.3 Direct connections.....................................................................................		65
6.2	Digitiser status streams.....................................................................................	66
6.2.1 GPS............................................................................................................		67
6.2.2 Graphing status information.....................................................................		69
6.3 The summary window......................................................................................		70
6.3.1 Timing.......................................................................................................		71
6.3.2 Mass position.............................................................................................		71
6.3.3 Age.............................................................................................................		72
6.3.4 Errors.........................................................................................................		72
6.3.5 Triggers......................................................................................................		72
6.4	The ViewInfo window......................................................................................	74
7 Configuring digitisers..............................................................................................		76
7.1	System ID..........................................................................................................	77
7.2	Output control..................................................................................................	78
7.3	Triggering..........................................................................................................	80
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7.3.1 STA/LTA....................................................................................................		81
7.3.2 Level...........................................................................................................		85
7.3.3 External triggering.....................................................................................		85
7.3.4 Pre-trigger and post-trigger recording.......................................................		86
7.4	Mux Channels...................................................................................................	86
7.5	Ports..................................................................................................................	87
8 Controlling digitisers...............................................................................................		89
8.1	System...............................................................................................................	89
8.2	Triggering..........................................................................................................	90
8.3	Calibration........................................................................................................	91
8.4	Mass Control.....................................................................................................	92
8.5	Data flow...........................................................................................................	93
8.5.1 DIRECT......................................................................................................		94
8.5.2 FILING.......................................................................................................		95
8.5.3 DUPLICATE...............................................................................................		96
8.5.4 DUAL.........................................................................................................		97
8.5.5 FIFO (First In First Out)............................................................................		97
8.5.6 ADAPTIVE.................................................................................................		98
8.5.7 Transmission mode summary...................................................................		99
8.6	Buffer Memory Usage.......................................................................................	99
8.6.1 RE-USE / RECYCLE...................................................................................		99
8.6.2 WRITE-ONCE..........................................................................................		100
9 Recording and playback.......................................................................................		101
9.1	Recording........................................................................................................	101
9.2	Files.................................................................................................................	103
9.2.1 UFF file format........................................................................................		106
9.2.2 MiniSEED file format..............................................................................		107
9.2.3 SAC file format........................................................................................		109
9.2.4 SUDS file format.....................................................................................		110
9.2.5 GSE file format........................................................................................		111
9.2.6 CSS file format........................................................................................		111
9.2.7 SEG-y file format.....................................................................................		112
9.3	Playback..........................................................................................................	112
9.3.1 GCF files..................................................................................................		112
9.3.2 Reading hard disks..................................................................................		115
9.3.3 SCSI tapes................................................................................................		116
9.4	Automatic playback........................................................................................	117
10 Printing options...................................................................................................		119
10.1 Page printout.................................................................................................		119
10.1.1 Automatic printing................................................................................		119
10.1.2 Automatic screen-shots.........................................................................		121
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	10.2	Continuous printout.....................................................................................	122
	10.2.1 Port capturing........................................................................................		125
11	Logging and notification.....................................................................................		126
	11.1	Log files.........................................................................................................	126
	11.2	E-mail notification........................................................................................	128
12	Extending Scream!..............................................................................................		130
	12.1	Installing new extensions.............................................................................	130
	12.2	Running extensions......................................................................................	131
13	Keyboard short-cuts............................................................................................		133
	13.1 The main window.........................................................................................		133
	13.2 Waveview windows......................................................................................		134
	13.3	Details window.............................................................................................	135
14	Inside Scream!.....................................................................................................		137
	14.1	Command line options.................................................................................	137
	14.2	The calvals.txt file........................................................................................	138
	14.3	File and directory locations..........................................................................	138
	14.3.1 Windows version...................................................................................		138
	14.3.2 Linux version.........................................................................................		139
	14.4	Error messages..............................................................................................	140
15	Revision history...................................................................................................		142

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1 Introduction

Scream! 4.5 is a software application for seismometer configuration, real-time acquisition and monitoring. It runs on Linux and Windows (from 98 onwards). It can be used for decompressing, viewing, printing, recording, transmitting and replaying GCF data from any Güralp Systems digital device.

Scream! 4.5 can be used in two modes:

•as a stand-alone, real time application for real-time data acquisition, including a network server and client, file replay, recording and analysis tools; or

•as a “helper” application for viewing pre-recorded GCF files, which also allows you to convert data formats and launch analysis tools.

1.1Scream! as a real time application

When you run Scream! by double-clicking on its icon, or by launching it from the command line, it opens a main window showing all the data streams coming in.

Scream! can listen for streams in GCF format on local serial ports or network interfaces.

The main window is the control centre for the whole program. If you close this window, Scream! will quit. All of Scream!'s functions are invoked from this window: see Chapter 3 on page 11.

You can view a data stream by opening a Waveview window for it. Any number of Waveview windows can be opened, each containing any number of streams. The same stream can appear in several Waveview windows, if desired. Each Waveview window has its own amplitude and time scaling, colour scheme, and display parameters. For example:

•a data stream can be viewed simultaneously at different zoom factors in different windows;

•different groups of data streams can be viewed simultaneously, each group having the same zoom factor; or

•an entire array can be monitored in one window, using another for detailed examination of incoming data.

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Waveview windows provide simple filtering capabilities, allowing you to examine seismic signals in a particular frequency range of interest. When more detailed analysis is required, data can be passed to a range of Scream! extensions with a simple selection.

Waveview windows are fully described in Chapter 4 on page 27; Scream! extensions are covered in Chapter 12 on page 130.

1.1.1 Diagnostic features

Scream! performs extensive checks on all incoming GCF data, and logs errors to disk. You can see details about the incoming data, including any errors detected by Scream!, using ShowInfo, Network Control, Summary and Status windows. These are described in Chapter 6 on page 63.

Scream! also provides logging facilities, and can e-mail operators when a potential problem is detected. See Chapter 11 on page 126.

1.1.2 Digitiser configuration

Scream! provides an easy-to-use graphical interface for configuring Güralp Systems digitisers. Output streams, triggering, calibration and mass control can all be managed by Scream!.

See Chapter 7 on page 76 and Chapter 8 on page 89 for more information on these features.

1.1.3 Networking

The real time Scream! application provides a built-in network server and client for data in GCF format. A Network Control window provides full control of Scream!'s network connections. The Scream! server can be configured to allow remote clients to configure digitisers and control instruments over the network.

Chapter 5 on page 53 describes the networking functions Scream! offers.

1.1.4 Recording and replay

You can instruct Scream! to record data to disk with the click of a button. Scream! supports GCF, SAC, miniSEED, SEGy, PEPP, SUDs and GSE formats, among others, allowing you to transfer the data quickly and easily for further analysis or processing.

GCF data files, including data from Güralp Systems NAM, EAM or DCM units, can be read, replayed at variable time-scales, viewed, converted or printed with a few mouse clicks.

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Support for SCSI tape devices is also included for secondary backup or large volume archival.

See Chapter 9 on page 101 and Chapter 10 on page 119 for details of these features.

1.2 Scream! as a data viewer

Scream! can also be run in a slimmed-down viewing mode, which loads in a GCF file, selection of files, or a directory containing files, and displays the data in a Waveview window.

To use these features:

•Double-click on a GCF file to open a WaveView window showing the data in the file.

Any valid GCF file can be loaded, including multi-stream files and files with gaps or out-of-order data.

•To open a WaveView window showing all the data in several GCF files, select the files, right-click and choose View in Scream from the pop-up menu.

•To search one or more directories for GCF files and display all the data in these files, select the directories, right-click and choose View in Scream.

WaveView windows opened this way behave exactly like windows from the real-time application, except that the “pause” button () is replaced with a button which resets the view to its initial settings.

You can design and apply filters, draw spectrograms, or send data to Scream! extensions just as you would from real-time Scream!. See Chapter 4 on page 27, for full details of what you can do.

From the command line, Scream! can be run in viewing mode with

scream -view filename [filename…]

Scream! cannot switch between real-time mode and viewing mode. If you want to load GCF files into the real-time application, you should use the Replay Files facility (see Section 9.3 on page 112). However, you can have both real-time Scream! and Scream! viewer windows open at the same time.

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2 Installation and Configuration

The Scream! software is available free-of-charge by request to mailto:[e-mail]. Please specify, when ordering, the operating system on which you wish to run the software.

2.1 Installation on Windows

Scream! for Windows is delivered as an installer packaged application so you will receive a single .exe file. Run this file and follow the instructions on screen. Please see Section 2.3 on page 10 for initial configuration steps.

2.2 Installation on Unix or Linux

Scream! for Unix/Linux can be delivered as either an RPM package or a .tar.gz compressed archive: please specify whichever is most appropriate when ordering. For users of Debian GNU Linux-based distributions, such as Ubuntu, the alien command can be used to create a .deb package from the RPM.

2.2.1 Installation from an RPM or .deb

You can normally use your package manager to install in the usual fashion. On some systems, however, you may need to use the ­­nodeps option with rpm, the ­­force­depends option with dpkg or a similar option with other package managers. Please see Section 2.3 on page 10 for initial configuration steps.

2.2.2 Installation from a .tar.gz archive

The archive is created with relative file-paths and contains, at its root, a single directory, scream-4.5. It should be unpacked (using tar ­xzf scream­4.5.tar.gz or an equivalent command) into a suitable location, such as /usr/lib. After unpacking, you need to copy a file to the system library directory (usually /usr/lib) and create a symbolic link. You normally need to have root authority to do this. Change your working directory to the scream-4.5 directory and issue the following commands:

cp libborqt-6.9.0-qt2.3.so /usr/lib cd /usr/lib

ln -s libborqt-6.9.0-qt2.3.so libborqt-6.9-qt2.3.so

You may wish to change the owner and group of the extracted files according to your local policy.

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Once fully installed, the application should be started by with the command /{install_path}/scream­4.5/scream. Please see Section 2.3 on page 10 for initial configuration steps.

2.3 Initial Configuration – all platforms

Scream!'s … screen	(available under the File menu) allows you,
amongst other things,	to set the location of data files and log-files. It

is wise to set these before proceeding. You can view the set-up screen at any time by keying + .

The directories in which you choose to place these files must be writeable by you. They will be created when needed (if they do not already exist) as long as the parent directory is writeable by you.

Configured paths are not parsed by any command shell, so sequences such as ~ (home directory for Linux/Unix users) or %AppData% (the application data directory for Windows users) will not do what you might expect.

As the data files can grow quite large, Windows users who use roaming profiles should pick a location which avoids having to transfer these files over the network each time they log on or off. Similar concerns may apply to Linux/Unix users in complex network environments.

The directory used for storing incoming stream data is set using the Base Directory item on the Files tab of the set-up dialogue. For detailed control of the file-names used, see Section 9.2 on page 103.

The directory used for storing logging information is set using the Directory item on the Event Log tab of the set-up dialogue. For more information, see Section 11 on page 126.

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3 The main window

When you start Scream!, you will be shown an empty main window:

Scream! is now ready for you to start adding data sources.

3.1Serial ports

1.Select File → Setup…. If the Com Ports tab is not visible, bring it to the front.

If you are running Scream! for the first time, this window will automatically appear, together with a short tutorial.

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2.The serial ports available to Scream! are listed in the table. Identify each port, and the instrument connected to it.

If you are using Microsoft Windows, the Port number corresponds to the COMn number of the serial port. If you are

using Linux, Port numbers 1 – 64 refer to the built-in serial ports /dev/ttyS0 – /dev/ttyS63. Ports 65 and above refer to USB-connected serial ports beginning /dev/ttyUSB0.

A port may not be listed if it is not installed, suitable drivers are not available or if another program is using it. Scream! scans your computer for new ports each time you open the Setup window. To make Scream! scan the ports again, click the Port column heading.

3.Configure each port according to the settings of the instruments connected to them:

Baud Rate : The speed of the serial link to the instrument. The current digitiser product range defaults to 38,400 baud. Older 3-channel Güralp digitisers default to a speed of 9,600 baud; 6-channel digitisers use 19,200 baud; EAM units use a baud rate of 115,200 by default. If you do not know the baud rate of your digitiser's output port, select Auto-Detect from the drop-down menu to have Scream! attempt to detect it for you. The instrument must be producing data for this to work.

You can set all ports to the same baud rate by clicking on the column heading and choosing a suitable value from the drop-down menu.

If you are using Scream! for real time data, you will not need to change any of the remaining settings.

AutoBaud : Once connected, Scream! dynamically alters its baud rate to fit with the instrument to which it is connected. However, this can interfere with transmission over very noisy links. If you have problems, clear this box.

ACKs : Whether Scream! should send Acknowledged messages to this instrument.

NACKs : Whether Scream! should send Not Acknowledged messages to this instrument, when it detects a failure in transmission.

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BRP : Whether Scream! should attempt to recover dropped blocks from the instrument using the Güralp Block Recovery Protocol. You should clear this box if you are using a single-direction (simplex) communications link.

If you clear all three check-boxes (ACKs, NACKs and BRP), Scream! will never acknowledge data packets that it is sent. This is particularly useful in situations where you need to connect to a digitiser without altering the flow of data. For example, a digitiser in FIFO or ADAPTIVE mode will normally save data in Flash memory only if data packets are not acknowledged. When you come to download the saved data from such a digitiser, you should clear these check-boxes before connecting the digitiser. Doing this will ensure that incoming data continues to be saved on the digitiser, rather than transmitted to Scream!.

Rx T/O (receive time-out) : The time, in seconds, that Scream! will wait for the sender to finish transmitting a block, before assuming that it is complete. If the instrument stops transmitting in the middle of a block, Scream!'s diagnostics will detect it and request retransmission next time the instrument is on-line.

You can tick or clear all the check-boxes in a column by clicking on the column heading.

4. Click .

If any instruments are connected, data streams should now begin appearing in the right-hand portion of Scream!'s main window.

Another way to configure a serial port is to right-click on its entry in the streams list (the left-hand panel in the main window) and selecting Configure… However, you can only do this if data have already arrived through the port, making it appear in the streams list.

From this page, you can double-click on the port number of an open Com port to go directly to a terminal session on that port.

If you want to access Scream! servers on the network (i.e. EAMs, or other instances of Scream!), you will need to add the servers to the list using the Network Control window. See Section 5.1 on page 53, for more details.

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Scream! will remember all the data sources you have specified on exit. When you next open the program, it will automatically try to re-establish all the connections.

3.2 The stream buffer

Scream! works by recording incoming streams into a fixed area of memory, called the stream buffer. All of Scream!'s operations work with the data in this buffer.

When you start Scream! for the first time, this buffer is empty. You can add data to it either by receiving it from local serial ports, connecting to Scream! network servers, or replaying GCF files.

Once the stream buffer is full, Scream! will start discarding the oldest data. If you have not told Scream! to record the incoming streams (see Chapter 9 on page 101), then you will not be able to get discarded data back.

You can change the size of the stream buffer in the Display pane of the Setup window (see Section 4.4 on page 48).

If you have enabled GCF recording, Scream! keeps track of the files which contain data in the stream buffer, and saves this information in a .lst file in the current recording directory (set using the Base Directory item on the Files tab of the set-up dialogue). When Scream! is restarted, it reads this file and tries to rebuild the stream buffer as it was when it was shut down. Otherwise, the buffer starts off empty as before.

3.3 The source tree

The tree in the left panel of the main window shows all the data sources currently connected to Scream!, whether local instruments, networked instruments, or files being replayed.

Scream!'s source tree has two main parts: Files, which contains all the files you have replayed (including automatic replay: see Section 9.3 on page 112), and Network, which represents your seismic network.

Beneath Network is a list of all the network servers Scream! is connected to, plus the entry Local for your computer's own serial ports.

The next layer contains the serial ports themselves. These icons are provided to help you identify the instruments, as well as providing direct terminal access.

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As an example, the screen shot above shows Scream! running on a computer which is not directly attached to any instruments. It receives data from a single network source, MACALLAN1, which has two serial ports Com1 and Com2. These ports are attached to the instruments BHOLE-BH05 and GURALP-DA79 respectively: if your installation uses a CRM (Combiner-Repeater Module) or EAM connected to a serial port, several instruments may be listed under a single serial port icon.

The MACALLAN1 server icon has been “unrolled” to reveal the serial port icons. You can “roll up” icons and save space by clicking on the box.

You can tell Scream! to ignore a particular instrument by right-clicking on its icon and selecting Ignore. When you do this, Scream! will discard any blocks it receives from the instrument. They will not appear in the stream buffer or be recorded to disk. Select Ignore again to stop ignoring the instrument.

3.3.1 Icons

Instrument icons change colour to provide you with a quick overview of the instrument's timing and mass position status:

If both halves of the instrument icon are clear , Scream! has not received any information from the instrument since the program started.

If the top half is green , the instrument has reported a satisfactory timing fix.

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If the top half is yellow , the instrument has reported a gap in the timing stream. This will occur if the GPS signal deteriorates to the point where the receiver cannot keep a lock on the satellites.

If the top half is red , the instrument has not reported a satisfactory timing fix for over an hour. This will happen if the instrument has reported failures (as above), but also if it has not reported anything. If you have set the GPS system to power down for intervals longer than an hour, the icon will turn red even if the system is working normally.

If the bottom half is red , the instrument (or one of its components) is running with a mass position over 15000 counts—roughly 50% of its travel. You should re-centre the component if possible, to avoid clipping after large ground movements.

If the instrument appears as a green box , the instrument has sent status blocks to Scream!, but no data. The box represents a Güralp CRM/SAM; these modules store or forward data from other instruments, but occasionally produce status blocks themselves. If a digitiser produces a status block before any data, perhaps because you have configured very slow data rates, or are using FILING or DUAL transmission modes (see Section 8.5 on page 93), it will temporarily appear with this icon.

3.4 The stream list

If Network is selected in the source tree, the right-hand panel will list all the data streams which Scream! receives (and is not ignoring). If an entry in the source tree is selected, the stream list will only show the streams beneath that entry—selecting a serial port will only show streams from instruments connected to that port, and so on.

The columns in the table provide useful information about each stream.

Stream ID : A unique name for the data stream, being a combination of six letters A – Z and numbers 0 – 9. The first four characters of this name identify the digitiser, and the last two characters identify the individual stream.

The first four characters are set by default to the serial number of the digitiser; you can change this on the System ID pane of the Configuration Setup window (see Section 7.1 on page 77) or from the digitiser's console.

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The last two characters tell you the type, component, and output tap of the stream.

•Z0, N0, E0 correspond to input channels Z, N, and E of the digitiser's SENSOR A port, continuously output through Tap 0.

•Z2, N2, E2 correspond to the same input channels, output through Tap 1 at a lower sample rate.

•Likewise, Z4, N4, E4 and Z6, N6, E6 correspond to Taps 2 and 3.

•Z1, N1, E1; Z3, N3, E3; Z5, N5, E5; and Z7, N7, E7 correspond to Taps 0, 1, 2, and 3 of SENSOR B, when you connect a 6-channel digitiser.

•00 is the digitiser status stream (notice: zero sample rate).

•M8, M9, MA are slow-rate Mux channels reporting the sensor mass positions for the Z, N, and E components (Section 7.4 on page 86).

•MB is a slow-rate Mux channel used for user input, or calibration signals on older Güralp Systems digitisers.

•MC-F are further Mux channels, used for user input or the digitiser's internal temperature.

•X0-X7 denote the auxiliary analogue input channel on newer DM24 units, digitized using the same tap settings as Z, N and E.

•C0-C7 denote the same input channel, when it is being used for an input calibration signal.

•Z, N, EG-N are the channels Z, N, E0-7, respectively, when they output triggered data.

•IB denotes digitiser Information Blocks containing user information. Scream! tries to interpret these blocks and automatically extracts data from them for use in WaveView windows or Matlab extensions.

•CD, BP are digitiser streams for specialised use.

Scream! can replace these designations with more helpful names if you wish: see Section 4.4.2 on page 49.

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Rec. : Whether Scream! is currently recording the data stream to the computer's on-board hard disk (not the digitiser's memory). If another device on your network is recording the data stream independently of Scream!, the entry in this column will still be No. If this entry shows ERR, then there has been an error whilst writing data for this stream. Investigate the cause, then re-enable recording to clear the error.

Comp. : The compression factor of the data in the stream, expressed as the number of bits occupied by each record (8, 16 or 32 bits). This can vary block-by-block.

SPS : The sampling rate of the data stream, in samples per second. Status streams, ending in 00, do not constantly output data and have an SPS of 0. By default, the stream list is sorted in order of sample rate, with the status streams at the bottom.

End time and Date : the date and time of the most recent data, as measured by the data's own time-stamps. These are not necessarily the latest data to arrive.

RIC : The ‘Reverse Integrating Constant’. In effect this is the value of the last sample received. This is most useful for reading mass positions or other environmental streams. Status streams have a RIC of N/A.

If a stream is currently recording, on Windows the option “Explore Recording Folder” will open a Windows Explorer window at the folder where the data are currently recorded. This is useful to quickly browse to the recorded files.

3.4.1 Sorting options

Sorting options are available from the View → Sort By menu:

•Alphabetical : Strict alphabetical order, 0 – 9 then A(a) – Z(z).

•Component : Vertical components (ending Zx), followed by Nx and Ex components, then Mux channels Mx. Within a component type, sort by the first four characters of the Stream ID.

•Instrument : Sort by the first four characters of the Stream ID. Within an instrument, sort by tap, then by component.

•Sample Rate : Sort by sample rate, highest to lowest. Within a sample rate, sort as Instrument.

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•Tap : Sort by tap (the last character of the Stream ID). Within a tap, sort by instrument, then by component.

•Select the Reversed option to reverse any of these sort orders.

You can also sort the list by Stream ID or SPS by clicking on the relevant heading; click again to reverse the sort order.

3.5 The status bar

At the bottom of Scream!'s main window is a status bar containing summary information about Scream!'s state:

•The server address from where the data for the currently selected instrument is being received;

•The number of different data streams currently accessible from the window, including those that have been “rolled up”;

•The amount of memory currently being used by Scream!'s stream buffer. You can change the maximum size of the stream buffer from the Setup window (see Section 4.4.1on page 48). If this number approaches the capacity of your computer, it may become slow and difficult to use; and

•The current time, according to the local computer (not the timestamps of incoming data).

To disable the status bar, deselect View → Status Bar on the menu.

3.6 Viewing streams

Double-click on one of the streams to open a window for viewing the data, or right-click on it and select View…. Alternatively, make a

selection of streams from the list and double-click on the selection or press ENTER.

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Data streams are opened in a Waveview window:

This window allows you to see real-time data coming in. You can also pause the window and examine any features held in the stream buffer. For full information on the features provided by Waveview windows, see Chapter 4on page 27.

Status streams (ending 00) consist of plain text. Double-clicking on a status stream produces the Status window:

The first blocks will give the boot message from the digitiser, including its software revision and the data streams selected for downloading and triggering. Later blocks give information on visible GPS satellites, the location of the GPS antenna and time synchronization status. Also

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displayed are the baud rates currently used for each channel and for the data link.

For more information on status streams and GPS, see Section 6.2 on page 66.

If you View a selection which includes both status and data streams, the status streams will be collected together and displayed in a tabbed Status window, whilst the data streams will appear in a single

Waveview window.

3.7 Connecting to instruments

Digitiser configuration and other common operations can be performed from Scream! by right-clicking on the digitiser in the source tree and selecting Configure… or Control… See Chapter 7 on page 76 and Chapter 8 on page 89 for more information.

Scream! also allows you to access the serial terminal of any connected digitiser and issue commands directly, by right-clicking on it and selecting Terminal…. See Section 6.1 on page 63 for more information about the serial terminal.

An instrument may connected to Scream! through a series of other units (NAMs, EAMs, DCMs, etc). Scream! will negotiate with each unit in turn to reach the instrument you are interested in. However, the process may take a little time.

Right-clicking on a digitiser and selecting Triggers… brings up a window describing all the digitiser triggers that have been detected. This window can also be reached from the Summary window: see section 6.3 on page 70 for more information.

3.8 Calibration data

Scream! can display data streams from displacement, velocity, and acceleration sensors in physical units. To be able to do this, it needs to know the calibration information provided with the sensor and digitiser.

Newer Güralp digitisers transmit calibration information in an information block when they reboot. When Scream! receives an information block that it understands, it automatically extracts this information and remembers it.

You can also enter and edit calibration information manually. Right-click on the digitiser's icon and select Calvals…. A window will

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open with a text entry box. This window lets you edit Scream!'s calibration values file.

Fill in the text box with calibration information for your digitiser and the instrument connected to it, in the format described below.

• To set the serial number of the instrument, include the line

Serial-Nos=serial-number

Scream! cannot tell what instrument is connected to the digitiser. This line is provided to help you remember which set of calibration values you have used, and to provide a title for calibration graphs. If you attach a different instrument to the same digitiser, you will need to enter new calibration values to reflect the new instrument.

• To set the sensitivity of the digitiser, include the line

VPC=sensitivity

VPC stands for voltage per count, measured in units of μV/count. This is sometimes given as μV/Bit on the digitiser calibration sheet.

• To set the sensitivity of the calibration channel, include the line

CALVPC=sensitivity

as for the other digitiser channels.

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• To set the value of the calibration resistor, include the line

CALRES=resistance

Güralp Systems digitisers normally use a 51 kΩ resistor (CALRES=51000).

• To set the sensor type, include the line

TYPE=model-number

e.g. 3T, 5T, etc..

• To set the response of the sensor, include the line

RESPONSE=response-type unit

Some of the values you can use are given in the table below. If none of these match the response of your instrument, please contact support for advice.

	Sensor	Sensor type code	Units
			(V/A)
	CMG-5T or 5TD,
		CMG-5_100HZ	A
	DC – 100 Hz response
	CMG-40T-1 or 6T-1,	CMG-40_1S_100HZ	V
	1 s – 100 Hz response
	CMG-40T-1 or 6T-1,	CMG-40_2S_100HZ	V
	2 s – 100 Hz response
	CMG-40T-1 or 6T-1,	CMG-40_10S_100HZ	V
	10 s – 100 Hz response
	CMG-40T, 20 s – 50 Hz response	CMG-40_20S_50HZ	V
	CMG-40T, 30 s – 50 Hz response	CMG-40_30S_50HZ	V
	CMG-3T or 3ESP,	CMG-3_30S_50HZ	V
	30 s – 50 Hz response
	CMG-40T, 60 s – 50 Hz response	CMG-40_60S_50HZ	V
	CMG-3T or 3ESP,	CMG-3_60S_50HZ	V
	60 s – 50 Hz response
	CMG-3T or 3ESP,	CMG-3_100S_50HZ	V
	100 s – 50 Hz response
	CMG-3T or 3ESP,	CMG-3_120S_50HZ	V
	120 s – 50 Hz response

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Sensor

CMG-3T, 360 s – 50 Hz response

CMG-3TB or 3V / 3ESP borehole, 30 s – 50 Hz response

CMG-3TB or 3V / 3ESP borehole, 100 s – 50 Hz response

CMG-3TB or 3V / 3ESP borehole, 120 s – 50 Hz response

CMG-3TB or 3V / 3ESP borehole, 360 s – 50 Hz response

CMG-3TB or 3V / 3ESP borehole, 360 s – 100 Hz response

	Sensor type code	Units
		(V/A)
	CMG-3_360S_50HZ	V
	CMG-3B_30S_50HZ	V
	CMG-3B_100S_50HZ	V
	CMG-3B_120S_50HZ	V
	CMG-3B_360S_50HZ	V
	CMG-3B_360S_100HZ	V

Some English descriptions are also accepted, e.g. “120s velocity”, “100Hz acceleration” but this is not a free-format, parsed field.

•To set the sensitivity (or gain) of the sensor components, include the line

G=vertical-sensitivity,N/S-sensitivity,E/W-sensitivity

These values are given on the sensor calibration sheet. For

velocity sensors, they are given in units of V m-1 s (V/ms-1). The gain of an accelerometer is expressed in V m-1 s2 (V/ms-2). Because Güralp Systems sensors and digitisers use differential inputs and outputs, the sensitivity is quoted as

2 × (single-ended sensitivity) on the calibration sheet.

•To set the coil constants of the sensor components, include the line

COILCONST=vertical-constant,N/S-constant,E/W-constant

These values are given on the sensor calibration sheet.

• To set the local acceleration due to gravity, include the line

GRAVITY=acceleration

You should give this value in ms-2, if you know it. If you miss out this line, Scream! will use a standard average g value of 9.80665 ms-2.

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When you have filled in all the values, click .

Any WaveView windows that are open will change to show streams in physical units. New WaveView windows will also use these units where possible.

Each digitiser System ID and serial number can have only one instrument connected to it. If you have a 6-channel digitiser with two connected sensors, you will need to make the digitiser announce

different serial numbers for each one. On newer Güralp Systems DM24 digitisers, this can be done with the command SERIAL2. See

the manual for your digitiser for more information.

3.8.1 Examples

The calibration information for a CMG-3T weak-motion velocity sensor might look like the following:

Serial-Nos=T3X99

VPC=3.153,3.147,3.159

G=1010,1007,1002

COILCONST=0.02575,0.01778,0.01774

CALVPC=3.161

CALRES=51000

TYPE=CMG-3T

RESPONSE=CMG-3_30S_50HZ V

GRAVITY=9.80122

CMG-5TD accelerometers use 1 Ω calibration resistors, and their coil constant is set to unity. Older CMG-5TD instruments, based on Mk2 digitiser hardware, do not have calibration input facilities, and thus the CALVPC entry is omitted. For example:

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Serial-Nos=T5585

VPC=2.013,2.028,2.036

G=0.256,0.255,0.255

COILCONST=1,1,1

CALRES=1

TYPE=CMG-5T

RESPONSE=CMG-5_100HZ A

GRAVITY=9.81089

For information on the file, calvals.txt, which stores these values, see section 14.2 on page 138.

3.9 Other features

The main menu also provides some miscellaneous facilities.

Choose File → Save Program State to save Scream!'s configuration file immediately. This file is read whenever you start Scream!, and any

changes are written back whenever you close it. Under Microsoft Windows, the configuration file appears as scream.ini in the c:\scream directory; under Linux, it is saved in $HOME if this

variable is set, otherwise the same directory as the Scream! program file. You can change the name and location of the configuration file with a command line option (see Section 14.1 on page 137).

Choose File → Application Caption… to change the title of Scream!'s main window. This is useful if you have several copies of Scream! running on the same computer (e.g. to run multiple network services).

Choose View → Stay On Top to keep Scream!'s main window on top of all other Scream! windows at all times. Other applications may still cover Scream!'s main window.

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4 Waveview windows

The most commonly used features of Scream! are accessed through Waveview windows. You can open as many Waveview windows as you like, on any combination of streams; the same stream can be part of several Waveview windows at once, at several different scales.

To open a Waveview window from Scream!'s main window:

•select Window → New Waveview Window… from the main menu;

•double-click on a stream ID in the streams list;

•right-click on a stream in the list and select View; or

•make a selection of streams and double-click the selection (or press ENTER).

You can add further streams to the Waveview window by selecting them from the streams list and dragging the selection into the Waveview window, or by dragging them from other Waveview

windows. Dragging with held down will copy the stream from

one window to another; otherwise, the stream will be moved to the new window.

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If you are running Scream! in real-time mode, and you double-click on a GCF file to view it (or open the Scream! viewer in some other way), you will have both real-time and “view” windows open. In this case, you can drag streams from real-time windows to other real-time windows, but not from these to view windows, or from view windows to other view windows. This is because the windows are handled by different instances of the Scream! program.

You can also drag streams within a Waveview window to reorder them. (If you have paused a Waveview window with the icon (), you will need to drag from the panel on the left, since dragging across the window will zoom in; see below.)

To the left of the stream display is a panel identifying the stream by its System ID and Stream ID, or another label if you have set one (see Section 4.4.2 on page 49). If the label is too long to read, you can resize the panel by dragging its edge across the Waveview window. You can also hide the panel this way.

4.1 Window functions

Above the stream display is a toolbar, containing icons which act on all of the streams within the window.

4.1.1 Zooming in and out

To zoom in and out vertically, click the vertical scale icons

at the top left of the window, or use your mouse wheel. The current zoom factor is shown between the icons, as a ratio of pixels to counts. Zooming in and out affects every stream in the window.

To zoom in and out horizontally, click the horizontal scale icons

, or hold down the shift-key (

) whilst turning your

mouse wheel. The current zoom factor is shown between the icons, in pixels per second. To convert to pixels per sample, divide the zoom factor by the sample rate for the stream.

If you have a large window which takes some time to scroll, especially at a high horizontal zoom factor, Scream! may not be able to finish drawing new data before it needs to scroll again. If this happens, Scream! will delay scrolling until it can display in real time once more. To prevent this, decrease the time scale.

If you have paused the window with the icon, you can zoom into an area of interest by dragging a rectangle across the streams. Scream! displays the time span in the top right corner of the rectangle, and the

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number of counts in the bottom left corner. You can drag across one stream, or several; the resulting window will still include all streams.

Whilst the window is paused, you can also adjust the view start and end times by dragging the ends of the horizontal scroll bar button, at the bottom of the window.

4.1.2 Making measurements

Click the Time Cursors or Ampl Cursors button to display a pair of vertical or horizontal cursors. Each cursor has a square at one end, which can be dragged across the Waveview window to measure features. If two cursors coincide, you will only be able to see the squares.

The distance between the cursors is given in the text of the Time Cursors or Ampl Cursors icon, in seconds and Hz or counts. You can have both vertical and horizontal cursors active at the same time. Because the limit of accuracy of the cursors is one pixel, you should zoom in to the range of interest before measuring.

The Ampl Cursors measure distances in counts according to the current zoom settings. However, if you have applied a scaling factor to an individual stream (see below), the Ampl Cursors do not take this scaling into account, so the measured distance will no longer be in digitiser counts; they will be in the scaled units of the stream.

To obtain the true value in counts, divide the value displayed in the Ampl Cursors icon by the scale factor for that stream, as displayed beneath its ID on the left-hand panel.

If a stream is shown with a physical unit (e.g. nm s-1), Scream! has scaled it so that the Ampl Cursors display a value in that unit. To do

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this, Scream! needs to know the sensitivities of your digitiser and instrument (see Section 3.8 on page 21).

4.1.3 Printing

To print the data currently being displayed in the Waveview window,

click on the Print icon . Scream! will use the current default printer settings to print a full page view of the window, using the current amplitude and time scaling, filtering and other display options. You can print at any time, in either real-time or paused mode.

To print the same data in black and white (on a colour or grey-scale printer), click on the arrow beside the Print icon and select Page Print (monochrome) from the drop-down menu. Black and white output is more suitable for copying or faxing.

You can also set up Scream! to print automatically, or send data directly to a connected plotter. For full details on the printing options available in Scream!, see Chapter 10 on page 119.

Note: The “print” facility is a good way to produce PDF outputs of waveforms, by using a PDF printer-driver (e.g. PDFcreator).

4.1.4 Filtering

Clicking the Filter icon makes Scream! apply a filter to each of the displayed streams. Click the icon again to disable the filter.

Scream! can be configured to apply different filters to each WaveView window. To select the filter, click on the arrow beside the Filter icon.

Adrop-down menu will appear.

•Select Default filter to apply Scream's built-in FIR bandpass filter. The properties of this filter depend on the sample rate of the stream. Data at 1 or 2 samples per second are filtered with a 10 – 30 second pass-band, whilst data at other sample rates are filtered with corner frequencies at 0.1 and 0.9 times the Nyquist frequency of the stream. For example, the pass band for the filter applied to a stream at 100 samples per second will be 5 – 45 Hz.

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