CMG-DCM Data Communications Module Operator’s guide Part No. MAN-DCM-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.
CMG-DCM Table of Contents 1 Introduction............................................................................................................................5 1.1 Inside the DCM................................................................................................................7 Serial port services.............................................................................................................8 Network services..................................................................
Operator's guide 4 Configuration options..........................................................................................................40 4.1 General...........................................................................................................................40 4.2 Disk................................................................................................................................41 4.3 Serial port configuration..........................................................
CMG-DCM Tamper lines....................................................................................................................80 Disk Status ......................................................................................................................80 Software Versions............................................................................................................81 6 Inside the DCM...............................................................................................
Operator's guide 1 Introduction The CMG-DCM is a versatile Linux-based module for storing and transmitting data captured using Güralp Systems Limited's range of seismic measuring equipment. Data can be gathered from up to three digitizers compatible with the Güralp Compressed Format (such as the Güralp CMG-DM24), and stored in its on-board Flash memory, from where it is written from time to time to a USB hard disk or to another device on your network.
CMG-DCM Retrieving data from a DCM's disk can be done by plugging it into a computer compatible with the USB or FireWire mass storage standards. Disks can be swapped at any time with no risk to data. • A stand-alone DCM can also be supplied in a form factor suitable for mounting in a standard 19” rack. Such a DCM will normally come equipped with eight additional serial ports TTS0-7, and an optional State of Health (SOH) interface for monitoring or tamper evidencing.
Operator's guide This form of DCM uses an integrated 26-pin connector to communicate, rather than having separate ports. A DCM in any of these forms may be supplied in the configuration most suitable to your requirements, depending on how you wish it to be connected to your network, and how its USB interface is to be used. The two sets of options are independent. • Using the 10BaseT Ethernet network option, you can connect the DCM to any TCP/IP network.
CMG-DCM The two main areas which need to be configured determine the different services which the DCM provides from its serial and network ports. Serial port services You can use either the DCM's console or its Web configuration interface to configure the serial data ports. The serial.x.service configuration option determines which service each port provides. • The simplest service is getty. This creates a console port, which you can use to log in to the Linux operating system of the DCM directly.
Operator's guide do not have a DHCP server, you will have to set the IP address yourself. 2. Find out the IP address the DCM is using (if you have not set it yourself). 3. If necessary, configure your own computer's IP address so that it can communicate with the DCM. See Section 2.4, “Connecting to a local network” for full details. Once you have connected the DCM to your local network or to the Internet, you can use a wide range of methods to retrieve data from it.
CMG-DCM 2 Installing the CMG-DCM 2.1 Overview The DCM is effectively a low-power Linux computer dedicated to seismic data flow tasks. Resources permitting, the DCM can perform any computational task you require. Because of this flexibility, the DCM must be configured for your particular purposes before it can be used: 1. If you only need to use the DCM as a data store, you can gain console access over the serial port for configuration. 2.
Operator's guide A rack-mounted DCM has a separate POWER IN connector on the back panel, which should be attached to a 12 V DC supply. There is also a POWER OUT connector on this panel, which allows you to daisy-chain several DCM units together. The POWER OUT connector is provided merely for convenience: lines from the POWER IN connector pass straight through. An integrated DCM receives its 12 V DC power from two pins in its single connector.
CMG-DCM 5. You now have access to the DCM's console and all of its functions. You should change your password, if you have not done so already, with the command passwd For full details on how you can configure the serial ports of the DCM, see Section 4.3, “Serial port configuration”. Connecting over Ethernet You can use a “crossover” Ethernet cable to connect the DCM directly to your computer.
Operator's guide opening its Web site at http://192.168.0.2/ 7. Advanced usage: If you later want to connect your computer to a local area network, you can make the DCM visible to that network by setting up a network bridge. Before doing this, you must make sure that the IP addresses you have chosen for the DCM and your computer are suitable for the local network you want to connect it to.
CMG-DCM 2.4 Connecting to a local network The DCM is normally supplied with a 10BaseT Ethernet port. This port can be used to connect to your local network. When the DCM starts up, it will try to find a DHCP server on your network to assign it an IP address. If you use DHCP on your network, and you want to access the DCM's Web server or console over the network, you may be able to find out from the DHCP server which address it has given the DCM, in which case you can access it directly.
Operator's guide If you are connecting the DCM to a machine on the same network, you do not need to configure any more options at this stage. If your network uses DHCP, you will not need to perform this step. Instead, ensure the DCM is also using DHCP with gcfgdbset net.eth.0 dhcp/bootp 5. Issue the command ifconfig The DCM will reply with technical information on its current network setup. Each interface is listed separately.
CMG-DCM The options will take effect immediately whenever possible. Some changes may take some time to complete, since services may need to be restarted. The gcfgdbset command performs only simple checks on the new value, so you should check the syntax of the option carefully. Wi-Fi Optionally, a DCM may be supplied with 802.11 (“Wi-Fi”) hardware in place of Ethernet. There are two modes in which an 802.
Operator's guide of intermediate machines which support SSH. Once this chain is set up, you can treat the connection as if it were a direct link between the DCM and your computer. Many standard Internet protocols may be fed through SSH in this manner. Whether this is possible will depend on the precise configuration of your local area network. For more details, please see the documentation for SSH clients such as ssh and putty. 2.
CMG-DCM gives you access to all the module's configuration options. You can use this Web interface over any network connection using the HTTP or HTTPS protocols. Alternatively, you can log in to the DCM's Linux operating system and issue commands directly: see Section 6.2, “Command line tools”. Web setup The DCM provides a Web interface which you can use to set up the system. To access this from anywhere on the local network, open any web browser and navigate to the IP address of the DCM.
Operator's guide current contents of the on-board Flash memory. The links in the menu on the left lead to various pages where you can change the configuration of the DCM. Initially, you should be sure to change your administrator password. Click on Administrators under Network configuration, fill in the new password in the two text boxes below Existing accounts, near the bottom of the page, and click Change password.
CMG-DCM A useful feature of Güralp Systems digitizers is the ability to output streams at several data rates. Each stage of filtering is known as a tap, producing data at a particular rate. At each tap, incoming data is filtered and its data rate reduced by a user-selectable factor of 2, 4, 5, 8, or 10 (in the case of Güralp DM24 digitizers). The data rate at each tap must be an integer number of Hz. For a full listing of the possible tap configurations, see Section 5.2, “Digitizer Setup”.
Operator's guide 3 Usage The DCM can be integrated with any system where seismic data needs to be collected, collated, or converted from one form into another. It is designed to operate as transparently as possible, and once connected and configured for a particular role in a system it should not require further maintenance. The rest of this chapter gives detailed installation and usage notes for several common DCM installations. Between them, they highlight many important features of the DCM.
CMG-DCM 3. Connect the NETWORK socket to a computer as described in Section 2.4, “Connecting to a local network” and perform any necessary configuration of the DCM and digitizer. You will be prompted for a username and password: log in as root and use the password supplied by Güralp Systems. 4. The DCM will immediately begin recording data into Flash memory as it is received, and every so often data will be moved onto the internal hard disk. At this point you can leave the DCM running without assistance.
Operator's guide Slide the disk out and replace with another Lacie U&I drive, or any brand of IDE / USB or IEEE 1394 2.5” drive you specify (at the time of manufacture). You can do this at any time without losing data. 7. Plug the hard disk into any computer that supports the USB Mass Storage standard using a standard USB cable. Newer Linux distributions and Microsoft Windows XP have this enabled by default.
CMG-DCM 8. Double click on the drive's entry to browse the files inside and copy them to your data store. Alternatively, you can open the files directly from the USB disk using Scream! or other GCF-compatible software. 9. When you want to remove the USB disk, double-click on the Safely Remove Hardware button: 10.Choose the USB port attached to the disk, and click Stop.
Operator's guide 11.In the next window, check that the correct hardware is shown, and click OK to confirm. 12.You can now remove the hard disk from the computer and reinstall it in the DCM if required. 3.3 The DCM as a GCF data source With a sufficiently fast serial link, you can instruct the DCM to send incoming data directly to a GCF-compatible client. For example, Güralp Systems' Scream! software allows you to display and record incoming data, as well as change the settings of attached digitizers.
CMG-DCM 3. Either use a computer connected to the NETWORK port to browse to the Serial port configuration section of the DCM Web site, or log in to the Linux console over the serial link. 4. Set the serial.2.service option to gcf_out. If using the Linux console, this can be done using the command gcfgdbset (see Section 6.2, “Command line tools”.) Note: Beyond this point you will not be able to use the serial link to access the Web configuration interface of the DCM.
Operator's guide straight to the login: prompt by connecting direct to the serial port and typing forcegetty It may take several attempts for this to succeed. Sensor arrays Another possible reason for setting the DATA OUT port's service to gcf_out is to allow several DCM units to work together and aggregate the inputs from an array of sensors.
CMG-DCM 3.4 The DCM as a network data hub The most flexible way to operate the DCM is as a fully independent machine on your local area network. To do this: 1. Connect Güralp digitizers to PORT A and PORT B as necessary, using the serial data cable provided. 2. If you are using the DCM's USB capabilities, connect your external hardware or computer to the USB socket. Note: USB distinguishes between hosts and clients. The DCM can act as either, depending on the options you specified at manufacture.
Operator's guide By default you can use either http: or https: URLs to access the DCM's Web site. HTTPS is a secure variant of HTTP, which we recommend you use in preference to avoid passwords being sent over the network in clear text. Scream! and similar software applications should also be configured to use this IP address to communicate with the module. If the DCM is using a static IP address, you may assign it a name on your network (although you will still need to use the numeric IP address in Scream!.
CMG-DCM Port 2, Key 7002, name Port A, device /dev/ttySA2, baud 19200 Each port will be listed, with its number (e.g. 0), name (e.g. Data out port), and device (e.g. /dev/ttySA0). Configuring digitizers You can configure digitizers directly using the above commands. However, the DCM also provides a Web interface to the digitizer's configuration options. 1. Choose the entry for the relevant port under Actions → Digitizer Setup on the menu tree. 2.
Operator's guide When you are done, click Configure instrument to submit the changes to the digitizer and reboot it. For full details on the configuration options available, see the documentation for the DCM or the digitizer. You can also configure digitizers from within Scream!, if you enable the DCM's Scream! server (see “Real-time data transmission” in Section 3.4.) Data storage and retrieval All data received by the DCM is periodically written from Flash memory to the on-board hard disk.
CMG-DCM Other command line tools are available for manipulating the files on the DCM's hard disk. See the manual for full details. Using miniSEED format You can instruct the DCM to record data to Flash (and, later, its hard disk) in miniSEED format with the command gcfgdbset disk.recordas.miniseed yes or by selecting yes for the disk.recordas.
Operator's guide Click Save changes to save the configuration and start writing SEED volumes. One volume will be written for each stream every three hours. The DCM will always start a new volume if it is power cycled; the aborted file will still be a valid SEED volume. Real-time data transmission You can use the DATA OUT port (or any of the DCM's serial ports) in several ways, depending on the service you have chosen to run on the port.
CMG-DCM for client requests, you will receive a GCFACKN message from the server which will also appear in the Control pane. 6. Request data by right-clicking on the server and selecting GCFSEND:L (or GCFSEND:B) from the pop-up menu.(L is used for little-endian and B for big-endian byte order, and are distinguished for compatibility.) Streams should soon begin to appear in Scream!'s main window. 7. To stop the link, right-click as before and select GCFSTOP from the pop-up menu.
Operator's guide You can now enable the AutoDRM system under Data transfer—AutoDRM. Click Save changes to start the service. To test the AutoDRM system, send the following e-mail to the DCM: From: your@e-mail.address To: autodrm@your.DCM BEGIN GSE2.0 MSG_TYPE request MSG_ID unique-identifier HELP EMAIL your@e-mail.address STOP where your@e-mail.address is the e-mail address to send the return message and unique-identifier is a string which you can use to identify your request. autodrm@your.
CMG-DCM If the DATA OUT port is not responding at all, check the power supply to the DCM. I cannot see the DCM's Web site over HTTP or HTTPS. There is a problem with the network setup. Connect to the DCM's DATA OUT port using a terminal program and change the network settings to suit your network. In particular: • If the DCM has a static IP address, use ifconfig to verify that the DCM is using the correct IP address. If it is not, change it with gcfgdbset net.eth.0 static gcfgdbset net.eth.0.netmask 255.
Operator's guide I can GCFPING the DCM's Scream! server, but no data appears. Check the DCM is receiving data by selecting Actions → Data Viewer on its Web site. This is a Java applet which provides some of the functionality of Scream!, allowing you to check that data is being received correctly. The streams being received at the DCM are listed in the bottom section of the applet. Click on a checkbox to add that stream to the main viewer window.
CMG-DCM digitizer in the FILING or DUAL filing mode, it will send heartbeat messages to Scream! clients every so often. The DCM will not show these messages in the Data Viewer.) • If the digitizer does not respond when you press ENTER, or produces garbage, check that the DCM is using the same baud rate as the digitizer. By default, digitizers use a baud rate of 9600, with 8 data bits, no parity bit and 1 stop bit, and no flow control.
Operator's guide The DCM receives streams, but gaps appear in the data some minutes after boot-up. Check that the baud rate between the digitizer and the DCM is sufficient for all the data streams you want to transmit. If it is not, the digitizer's output buffer will gradually fill up until no more data can be stored. Increase the baud rate of the digitizer through the DCM (or using Scream!), then set the baud rate of the DCM's input port to the same value.
CMG-DCM 4 Configuration options All DCM modules feature an on-board Web server, which you can use to set up the unit.When you first connect to the module, you will be shown a menu tree in a panel on the left, with a summary of its current status (see Section 5.7, “Summary”) on the right. Links in the section of the menu tree marked Configuration allow you to change the settings used by the DCM itself.
Operator's guide 4.2 Disk This page allows you to change how the DCM will use its hard disk, and what data it will record on it. If you want to check that the hard disk is working, explore its contents, or format it, you should use the Disk tools page instead (see below.) The first three options allow you to specify formats in which the DCM should record data. There are three options: gcf, miniSEED and sac.
CMG-DCM disk.recordas.seed : Set this to yes to have the DCM record full SEED volumes on the hard disk. This option will have no effect until you create a datatransfer.seed.config file. See “SEED” in Section 4.5 for information on these options. disk.recordas.sac : Set this to yes to have the DCM record files in sac format. The next set of options allows you to select the data sources for archival. disk.recordfrom.serial.n : Each of these options refers to a serial port on the DCM by its number.
Operator's guide • The recycle option causes the DCM to overwrite the oldest data on the hard disk with incoming data. This way, the end point of the stored data is known (it always includes the most recent block of data), but the start point depends on the disk capacity. disk.writeinterval : This setting alters how frequently the DCM will write data to the hard disk. There are four manual timescales available: 1 hour, 4 hours, 1 day, or 1 week.
CMG-DCM The stand-alone DCM has three RS232 serial ports brought out on 10-pin milspec connectors, labelled PORT A, PORT B and DATA OUT. The labelling is provided for convenience, and can be ignored if it does not match your site requirements: each port may be used for communication in either or both directions. Each serial port has its own configuration screen, with a number of options beginning serial.x (where x is the internal number of the serial port).
Operator's guide command pppd to establish these links. pppd is a versatile program, which uses command-line options to specify the type of PPP link required. These options are fully described in the Linux documentation for pppd. The serial.x.ppp box allows you to specify pppd options to use on this serial port. Options which you wish to apply to all serial ports running the ppp service should be placed in the /etc/ppp/options file (see “options” in Section 4.4.) serial.x.
CMG-DCM control attached digitizers using its own interface. 4.4 Network configuration These settings must be provided if you intend to connect a DCM to a TCP/IP network, whether over a serial link via PPP, or using Ethernet or wireless connections. Ethernet port The settings described below begin net.eth.0 because they refer to the first Ethernet interface. If the optional 802.11b (“Wi-Fi”) hardware is installed, the settings on this page will begin net.wlan.
Operator's guide net.eth.0.broadcast : The broadcast IP address used by the interface. This can often be derived from the IP address by replacing numbers at the end with 255. net.eth.0.gateway : The IP address of the gateway machine (router) on your network. net.eth.0.netmask : The network mask to use for the IP interface. A DCM with an IP address in the domain 192.168.1.x would normally use a netmask of 255.255.255.0. net.eth.0.netaddress : The network address of the DCM.
CMG-DCM DNS setup net.dns.domain : The name of the domain containing the module. For example, a DCM at myinst.bignet.org would have its domain set to bignet.org. The rest of the settings on this page determine how the DCM determines the addresses of other hosts on the network from their host names. net.dns.search : If the DCM encounters an unqualified hostname in any of its configuration settings, or in a command, it will look for that name in each of the domains specified here in turn.
Operator's guide Incoming mail setup This page enables you to set up the DCM to retrieve e-mail from a POP3 or IMAP server on the network, either unencrypted or secured using TLS (transport-layer security.) If you do not need the DCM to be able to fetch mail, select None from the net.mail.in.type drop-down menu and ignore the remaining settings. net.mail.in.password : The password needed to log in to the mail server. net.mail.in.port : The number of the port to connect to on the mail server.
CMG-DCM Outgoing mail setup This page enables you to send mail from the DCM using the SMTP protocol. Both authenticated (i.e. sending a username to the server) and unauthenticated SMTP are supported, as is encryption using TLS (transport-layer security.) If you do not need the DCM to be able to send mail, select None from the net.mail.out.type drop-down menu and ignore the remaining settings. net.mail.out.
Operator's guide Remote access The settings on this page determines which ways you can use to access the DCM over a TCP/IP network. If all these methods are disabled, you may still be able to connect to the DCM over a serial link using getty (see serial.x.service, above), or over a direct modem connection. Your settings will come into effect as soon as you click Save settings, so you should ensure that you have a backup means of communication with the DCM before disabling these methods. net.remoteaccess.
CMG-DCM Administrators Users of the DCM can be one of two kinds. • Unprivileged users can log in or view the Web interface of the DCM, including its current configuration, but cannot change any of the options, nor configure any instruments attached to the DCM • Administrators may change settings or configure attached digitizers as they please. You may want to give different users separate accounts for tracking or other purposes, or to allow users to set their own preferences when logging in.
Operator's guide To remove a user account, choose their username from the drop-down box below Existing accounts and click Delete user. If you delete your own account, you will no longer be able to log in to the DCM, although you may finish what you are doing in the current session. You can also change the password for any account, for example if you believe it to have been compromised, or if you are assigning it to a new person.
CMG-DCM You can specify additional options for each serial port separately using the serial.x.ppp configuration option, which can be found on the Serial port configuration page for that port. chap-secrets The file /etc/ppp/chap-secrets contains secrets for pppd to use when it authenticates itself to other systems, and also when it authenticates other systems to itself.
Operator's guide the file, or the Linux info documentation for mgetty. 4.5 Data transfer You may retrieve data from the DCM using a variety of standard seismic protocols and formats. In addition, the DCM includes facilities for communicating with Güralp Systems' own Scream! PC software. The options on this set of pages allow you to configure the DCM to use these additional methods. Scream! Scream! is a Microsoft Windows software package designed to configure and retrieve data from Güralp digitizers.
CMG-DCM datatransfer.scream.server.port : The network port number which Scream! should use to connect to the DCM. You can use any port which neither the PC nor the DCM is using for other purposes. See your Scream! configuration for the current port setting; the default is 1567. datatransfer.scream.sampleratelimit : The fastest sample rate allowed for transmission over this connection.
Operator's guide HTTP server In addition to configuring the DCM and instruments attached to it, you can also instruct the on-board Web server to provide data to network clients. datatransfer.http.server : Select on if you wish to be able to retrieve data from the DCM over the Web (i.e. HTTP). Once the HTTP server is enabled, you can browse through the DCM's hard disk using the URL http://mydcm/cgibin/explorefs?path=/. You may need a username and password to access this service.
CMG-DCM will be several sender pages, all with the same options. datatransfer.cd1.sender : Select on to activate the CD1.0 sender. If you do not want the DCM to transmit CD1.0 data, select off and ignore the remaining settings. datatransfer.cd1.sender.sitename : The CD1.0 site name for the DCM. datatransfer.cd1.sender.receiver : The IP address or hostname of the remote CD1.0 device. datatransfer.cd1.sender.port : The network port number to which the DCM will send CD1.0 data. datatransfer.cd1.sender.
Operator's guide ignore the remaining settings. datatransfer.cd1_1.creator : An 8-character string specifying the source of the data (i.e. the instrument or array to which the DCM is attached.) datatransfer.cd1_1.destination : An 8-character string specifying the intended destination of the data. datatransfer.cd1_1.port : The network port number to which the DCM will send CD1.1 data. datatransfer.cd1_1.protocol : The network protocol the DCM should use to send CD1.1 data—currently only tcp is supported.
CMG-DCM key-bucket : the key-bucket code, which tells the DCM which key to use for that particular stream. The cryptographic hardware required to produce authenticated CD1.1 streams is installed only in Authentication Modules (AMs). To transmit unauthenticated CD1.1 data, you should use a key-bucket code of -1. prefix : A prefix used to determine where to place generated CD1.1 subframes. For example, a prefix of /data/HPA1. will produce files in the /data/ directory beginning with HPA1.
Operator's guide subscription list. • Receiving a valid DSS_DEL packet, dssserver will find the corresponding request in the subscription list, remove it, and reply with a DSS_ACK packet. If the relevant data has already been transmitted, dssserver will still send the DSS_ACK packet to notify the client that the request has been dealt with. • dssserver keeps a record of the subscriptions for each client so that it can respond to DSS_LRQ packets.
CMG-DCM typical line from the /etc/dss.cfg file might thus look like HPAAZ0:VCXX:VC:BHN The station name and location name must be equal to or less than 4 and 2 characters long respectively. The seedname should be a three-character string specified according to the SEED channel naming conventions. In particular, seednames for vertical components should end in Z, those for N/S components in N, and those for E/W components in E.
Operator's guide The Web interface does not check that the content of the files will be understood. You should ensure that the file is valid before committing any changes. The format of the file is as follows: HPA1Z2:::::CMG-3_120S_50HZ:CMG-DM24mk3:V9.800E-01:1.6E-07:46 HPA1N2:::::CMG-3_120S_50HZ:CMG-DM24mk3:V9.400E-1:1.6E-07:46 HPA1E2:::::CMG-3_120S_50HZ:CMG-DM24mk3:V1.050E00:1.
CMG-DCM • a case-sensitive code for the sensor type (see Appendix B.2, “Digitizer type codes”); • a case-sensitive code for the digitizer type (see Appendix B.2, “Digitizer type codes”); • the sensitivity of the sensor, prefixed with a V for a sensitivity in V/m/s, or A for a sensitivity in V/m/s2 (in the example, around 1 V/m/s). Note that there is no colon between the sensitivity and its unit. The sensitivity is given on the sensor's calibration sheet.
Operator's guide 5 Actions 5.1 Data Viewer The Data viewer page uses a simple Java applet to enable you to check that the DCM is receiving data correctly. Your browser must have Java installed for you to be able to do this. The data viewer is not intended to be a fully functional data visualisation tool. Scream! and similar software packages offer a full range of facilities for displaying and manipulating seismic data, either as it arrives or from stored data files.
CMG-DCM The icon bar The bar at the top of the applet allows you to alter how the data is displayed. If you are familiar with Güralp Systems' Scream! package, you will recognise the icons in use here.
Operator's guide 5.2 Digitizer Setup This page allows you to set up Güralp instruments attached to any of the DCM's serial ports. Each of the links under Digitizer Setup in the menu tree represents one of the DCM's serial ports. Clicking on a port here causes the DCM to attempt to retrieve the current configuration of the digitizer attached to that port.
CMG-DCM alter the settings on the digitizer to reflect your choices; this done, you should see the message New configuration successfully saved to attached instrument. If the DCM is connected to a PC running Güralp Systems' Scream! software, you can also configure the digitizers from within Scream!. See the User Guide for your digitizer model for more details. General digitizer settings Baud rate : The speed at which the digitizer will communicate with the DCM, in bytes per second.
Operator's guide source (which may have its own GPS unit, or take signals from one of the radio time standards). The DCM can recognise GCF timing packets and will pass them on to all connected digitizers. GPS Power Cycle : If you have selected Garmin GPS as the timing source, above, this setting determines how often the attached instrument will power up the GPS receiver to obtain an accurate timing signal.
CMG-DCM The table to the right shows the current setting of the digitizer. For example: In this example, under normal conditions, • the Z and N data streams will be output by Tap 1 at a rate of 2000/10/4 = 50 Hz, and • the E data stream will not be output.
Operator's guide Trigger criteria The triggering algorithm applies a simple short-term average / long-term average calculation to the triggering stream. It works by identifying sections of an incoming data stream when the signal amplitude increases. The purpose of taking a short term average, rather than triggering on signal amplitude directly, is to make it less likely that spurious spikes will trigger the device. Averaging also introduces an element of frequency selectivity into the triggering process.
CMG-DCM low a value will result in spurious non-seismic noise triggering the system. Like the averages, their ratio is continuously recalculated for all components. Note that none of the boxes are allowed to be empty, and so you will need to enter the new value before removing the old one. Alternatively, you can use the up and down cursor keys to change the values.
Operator's guide some channels, you should uncheck Common values before altering them. If you are using Scream!, you can use the Control window to change the values of the STA and LTA periods, together with the Ratio, without restarting the digitizer. See the documentation for Scream! for more details. Since it is not generally advisable to trigger from broadband data, the digitizer provides a set of standard bandpass filters to apply to the data streams before they are tested for the trigger condition.
CMG-DCM Tap # Rate (samples/s) Bandwidth 1 (Hz) Bandwidth 2 (Hz) Bandwidth 5 (Hz) 2 0.1 – 0.9 0.2 – 0.9 0.5 – 0.9 1 0.05 – 0.45 0.1 – 0.45 0.25 – 0.45 As can be seen, the filter you choose defines the set of permissible sample rates. The spectral amplitudes for the various frequency responses available are shown in the figures below.
Operator's guide digitizer will output data on that channel to the DCM, which will then store or transmit it with the rest of the data, according to the way it is configured. Since it is an optional feature, the digitizer may not use the Pressure Mux channel to report pressure data. If this is the case, that channel may be used for another purpose. Likewise, the three channels marked Spare may not be used, depending on the optional features present in the instrument.
CMG-DCM 5.3 Disk tools The buttons on this page allow you to perform some important actions on the DCM's primary hard disk. By default, the module looks for a connected USB hard disk to use as its primary storage medium. If no suitable storage medium can be found, you will see the message Failed to find a USB disk when you attempt to perform any of these actions.
Operator's guide Whilst the DCM is copying the contents of the Flash memory to disk, you will be shown a log of its progress. The USB interface allows data transfer at a speed of around 100 Kb/s, so large files may take several minutes to complete. If an error occurs at any point, it will be marked in red. 5.4 Disk files This link allows you to browse through any files currently on the DCM's primary hard disk.
CMG-DCM • a code [Xx] describing the type of program and the importance of the message (e.g. all errors have E as the second letter: see the Linux man page for syslog for full details), • the name of the program (e.g. guardian_log) which generated the message, • the text of the message. 5.7 Summary This link displays a page summarizing the current setup of the DCM. When you first log in to the module over its Web interface, this is the page you are initially presented with.
Operator's guide RX bytes:290005 (283.2 kb) TX bytes:417231 (407.4 kb) Interrupt:42 Base address:0x8300 For further information, see the Linux manual page for ifconfig. DNS configuration This section reports the current status of the DCM's domain name resolution service. This is done by presenting the contents of the standard Linux /etc/resolv.conf file. # eth0 begin domain guralp.local nameserver 192.168.0.1 nameserver 192.168.0.2 # eth0 end For further information, see the Linux manual page for resolv.
CMG-DCM Flash Status This section reports the current contents of the DCM's Flash storage. There may be one or several partitions of Flash memory in use. If a partition is not in use, it will be empty aside from the standard directory lost+found. Otherwise, one or more GCF-format files will be shown, together with each file's size in bytes and the time it was created (Unix ctime).
Operator's guide To browse through the disk files, you should use the Disk files page, described above. Software Versions The final section lists the software currently installed on the DCM's Linux operating system, together with each program's version number. If you need to contact Güralp Systems about any of the installed programs, you should quote the version number in your correspondence.
CMG-DCM 6 Inside the DCM The DCM is a fully-functional, Linux-based computer system especially designed for handling seismic data. It can collect and store data from several sources and, if required, output it in your preferred format to other locations on your network or on the Internet. This is done in the following manner. Firstly, the DCM receives some data from an instrument connected to it.
Operator's guide Once the data is stored on the DCM, whether in Flash memory or on the hard disk, it can be retrieved • by a remote computer running Güralp Systems' Scream!, or other GCFcompatible software; • by another DCM or AM, also using GCF; • by setting up a CD1.0 or CD1.1 transmitter on the DCM; • by direct file transfer (using SSH, HTTP, HTTPS, etc.,) • optionally, by requesting the data using SeedLink or AutoDRM.
CMG-DCM Once the operating system is loaded, the main Flash memory blocks (where present) are mounted on /nand0 and /nand1. Incoming data, which may be from several sources, is combined into a single stream and placed in one of these blocks (whichever is less full). When in use, you can expect each to be between 50% and 75% full, with several da:ta files present. If the DCM is using GCF as its storage file format (recommended; see Section 4.
Operator's guide Whilst the DCM is copying the contents of the Flash memory to disk, you will be shown a log of its progress. The USB interface can transfer data at a speed around 100 Kb/s, so large files may take several minutes to complete. Once a file has been moved from the Flash memory to disk, any further data received which would otherwise be appended to that file will instead be placed in a new file in the Flash memory. Because of this, a stream may occasionally be fragmented.
CMG-DCM The following sections describe how to operate a DCM from the Linux command line, including descriptions of all commands unique to the DCM. Any of these commands can be included in your own shell script files, which can be run as services on the DCM or remotely using a ssh connection as required. If you need to compile your own C or FORTRAN programs to be run on the DCM, please contact Güralp Systems for assistance. 6.
Operator's guide gcfgdbmark dirty option-name-or-prefix : Enter this command to mark the named configuration option as “dirty” in the database. gcfgdbisdirty option-name-or-prefix (option-names-orprefixes...) : This command finds out whether any of the named options is marked as “dirty”. If none are marked, the command exits successfully; otherwise, it exits with a failure code.
CMG-DCM character, \n = newline, \r = carriage return, \a = bell, etc.) You can use \r to issue several commands to the digitizer in one session, since the carriage return will cause the digitizer to act on the previous command. Passing the -r option causes the digitizer to reboot automatically once the command is completed. This is useful if you are using gcli to change the configuration of the digitizer, since many options require a restart for any changes to take effect.
Operator's guide • the port's Linux device name, and • the baud rate currently in operation on the port. You can query a single port by using the port number or key as arguments to the gnblocks command: gnblocks 2 gnblocks 0x7002 gnblocks 28674 (In the last example, 28674 is the key ID 0x7002 expressed in decimal: hex 7002 = 7 × 163 + 2 = 28674.) Another way to find out the index, key ID, name or device name of a particular serial port is to issue the command serialmap.
CMG-DCM • whether the GPS has obtained a fix (0 = has not received any data, 1 = has not obtained a fix, 2 = has obtained a 2D fix, and 3 = has obtained a 3D fix); • the mode the GPS is running in (A = automatic, and M = manual); • whether or not the system clock is being controlled by the GPS (255 = on); • whether the GPS is currently powered up (255 = on); • the current measured offset between GPS and the internal clock, in units of 500 ns; • the current value of the “busy” counter, which count
Operator's guide 6.5 Updating the DCM Over the Internet The easiest way to ensure that your DCM has all the latest software packages is to update it over the Internet. The DCM is provided with a simple command-line script, upgrade, which checks for new versions of all packages in the distribution on the Güralp Systems Web site and installs them as necessary. It also rebuilds the configuration database to work with the new packages, resets it, and reboots the machine.
CMG-DCM ipkg remove gsl-backdoor to remove the package. This will not affect the operation of the system in any other way; however, it may prevent Güralp Systems' engineers from being able to assist you in the event of problems. ipkg can also be used for other package management tasks; however, if you remove software from the DCM, or replace packages with versions incompatible with the rest of the system, you risk leaving the unit in an unrecoverable state.
Operator's guide flashdcm -r root-file -b boot-file -s baud-rate -p rootpassword -d port where root-file and boot-file are the images you wish to transmit, baud-rate is the baud rate of the DCM's console port, root-password is the password of the user root on the DCM (not any other administrative account), and port is the port number of the serial interface (on the second computer or DCM) which you will be using.
CMG-DCM Appendix A Connector pinouts Appendix A.1 Modular DCM units PORT A and B This is a standard 10-pin mil-spec socket (02E-12-10S). The pinout is such that the port can be connected to the serial output of a DM24 digitizer using a straight-through cable. Pin Function A Power 0 V B Power +10 to +35 V C RS232 RTS D RS232 CTS E RS232 DTR F RS232 DSR G RS232 ground H RS232 CD J RS232 transmit K RS232 receive DATA OUT port This is a standard 10-pin mil-spec plug (02E-12-10P).
Operator's guide F RS232 DSR G RS232 ground H RS232 CD J RS232 receive K RS232 transmit USB connector This is a standard 6-pin mil-spec socket (02E-10-06S). Pin Function A +5 V DC (USB Type A pin 1) B Data –ve (USB Type A pin 2) C Data +ve (USB Type A pin 3) D 0 V (USB Type A pin 4) E Shielding F Switched power +10 to +35 V NETWORK connector This is a standard 6-pin mil-spec plug (02E-10-06P).
CMG-DCM Appendix A.2 Integrated DCM units DM/AM module output This is a standard 32-pin mil-spec plug (02E-18-32P).
Operator's guide Appendix B Sensor and digitizer types These codes are used in situations where the DCM needs to know the response properties of sensors and digitizers, e.g. when compiling full SEED volumes. If you are unsure about the code you should use, contact Güralp Systems. Appendix B.
CMG-DCM Appendix B.
