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. 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.
Issue B 2005-12-22
CMG-DCM
Table of Contents
1 Introduction............................................................................................................................5
1.1 Inside the DCM................................................................................................................7
Serial port services.............................................................................................................8
Network services...............................................................................................................8
2 Installing the CMG-DCM....................................................................................................10
2.1 Overview........................................................................................................................10
2.2 Power supply..................................................................................................................10
2.3 Connecting to a single computer....................................................................................11
Connecting over a serial link...........................................................................................11
Connecting over Ethernet................................................................................................12
Using an internal modem.................................................................................................13
Connecting over USB......................................................................................................13
2.4 Connecting to a local network........................................................................................14
Wi-Fi................................................................................................................................16
Connecting to the Internet................................................................................................16
2.5 Connecting digitizers and external hardware.................................................................17
2.6 Setting up the CMG-DCM.............................................................................................17
Web setup........................................................................................................................18
3 Usage.....................................................................................................................................21
3.1 General notes..................................................................................................................21
3.2 The DCM as a data store................................................................................................21
3.3 The DCM as a GCF data source.....................................................................................25
Accessing the DCM command line through gcf_out.......................................................26
Sensor arrays....................................................................................................................27
3.4 The DCM as a network data hub....................................................................................28
Communicating with digitizers.......................................................................................29
Data storage and retrieval................................................................................................31
Real-time data transmission.............................................................................................33
3.5 Troubleshooting DCM installations...............................................................................35
I cannot connect to the DCM's DATA OUT port using a terminal program...................35
I cannot see the DCM's Web site over HTTP or HTTPS................................................36
I cannot connect to the DCM's Scream! server................................................................36
I cannot GCFPING the DCM's Scream! server...............................................................36
I can GCFPING the DCM's Scream! server, but no data appears...................................37
The DCM is not receiving any data streams....................................................................37
The DCM is receiving streams, but they do not contain any data...................................38
The DCM receives streams, but gaps appear in the data some minutes after boot-up....39
The DCM receives streams, but 2-minute gaps appear in the data at 4-hour intervals.. .39
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4 Configuration options..........................................................................................................40
4.1 General...........................................................................................................................40
4.2 Disk................................................................................................................................41
4.3 Serial port configuration.................................................................................................43
4.4 Network configuration....................................................................................................46
Ethernet port....................................................................................................................46
Static routes.....................................................................................................................47
DNS setup........................................................................................................................48
Incoming mail setup........................................................................................................49
Outgoing mail setup.........................................................................................................50
Remote access..................................................................................................................51
Administrators.................................................................................................................52
PPP...................................................................................................................................53
mgetty..............................................................................................................................54
4.5 Data transfer...................................................................................................................55
Scream!............................................................................................................................55
Scream! Client.................................................................................................................56
AutoDRM........................................................................................................................56
HTTP server.....................................................................................................................57
HTTP client.....................................................................................................................57
CD1.0...............................................................................................................................57
CD1.1...............................................................................................................................58
DSS..................................................................................................................................60
SEED...............................................................................................................................62
5 Actions...................................................................................................................................65
5.1 Data Viewer....................................................................................................................65
The icon bar.....................................................................................................................66
The stream list.................................................................................................................66
5.2 Digitizer Setup................................................................................................................67
General digitizer settings.................................................................................................68
Digitizer output control...................................................................................................69
Trigger criteria.................................................................................................................71
Auxiliary (“Mux”) channels............................................................................................74
Sensor mass control.........................................................................................................75
5.3 Disk tools........................................................................................................................76
Partition, and format disk................................................................................................76
Check disk filesystem......................................................................................................76
Flush flash........................................................................................................................76
5.4 Disk files.........................................................................................................................77
5.5 Camera............................................................................................................................77
5.6 Recent Log Entries.........................................................................................................77
5.7 Summary.........................................................................................................................78
Network configuration ....................................................................................................78
DNS configuration ..........................................................................................................79
Data Out Port, Serial Port A, Serial Port B......................................................................79
Flash Status......................................................................................................................80
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Tamper lines....................................................................................................................80
Disk Status ......................................................................................................................80
Software Versions............................................................................................................81
6 Inside the DCM....................................................................................................................82
6.1 File systems....................................................................................................................83
6.2 Command line tools.......................................................................................................85
6.3 Configuration..................................................................................................................86
Digitizer console access...................................................................................................87
6.4 Monitoring......................................................................................................................88
Data flow.........................................................................................................................88
Digitizer status.................................................................................................................89
Tamper lines....................................................................................................................90
6.5 Updating the DCM.........................................................................................................91
Over the Internet..............................................................................................................91
From the hard disk...........................................................................................................91
Removing support packages............................................................................................91
The firmware...................................................................................................................92
Appendix A Connector pinouts.............................................................................................94
Appendix A.1 Modular DCM units......................................................................................94
PORT A and B.................................................................................................................94
DATA OUT port..............................................................................................................94
USB connector.................................................................................................................95
NETWORK connector.....................................................................................................95
Appendix A.2 Integrated DCM units...................................................................................96
DM/AM module output...................................................................................................96
Appendix B Sensor and digitizer types.................................................................................97
Appendix B.1 Sensor response codes...................................................................................97
Appendix B.2 Digitizer type codes......................................................................................98
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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. Once data is on the hard disk,
you can connect to the DCM by various means to retrieve it.
Depending on your site requirements, the DCM may be supplied in several
formats. Although these look different, they all share the same internal features.
• A stand-alone DCM, housed in a high-impact copolymer polypropylene
case, may be connected to a digitizer through mil-spec connector cables
and installed in a ground station or other location remote from the
digitizer and seismometer. The stand-alone DCM can accept data from
up to three devices connected to it through RS232 ports.
Stand-alone DCM units are normally supplied with high-capacity
removable USB/FireWire disks for data storage. These disks allow the
DCM to be used as part of completely autonomous installation in cases
where communications links are poor or non-existent.
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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.
Up to four modules may be mounted side-by-side in a 19” rack.
• An integrated or modular DCM may be combined with a digitizer and
seismometer to produce a single unit capable of measuring seismic data,
storing, and passing it on over a network:
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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.
• Alternatively, an internal PCMCIA modem may be supplied, through
which you can use a dial-up or other communications link to connect to
your home network. Most 56k analogue and ISDN-type modems are
supported.
• As a third option, an 802.11b Wi-Fi module may be installed.
• If the USB client option is installed, you can connect the DCM's USB
port to a computer and communicate with it as if it were on a private
network.
• If the USB host option is installed, you can connect the USB port to an
additional peripheral, such as a camera or external hard disk.
Whichever set of options you choose, you can use any free RS232 port to
connect the DCM to a single computer for local monitoring and configuration,
or through it to a wider network using PPP/SLIP.
1.1 Inside the DCM
The DCM's configuration is maintained by an internal database. All of the
flexibility of the unit is provided through this configuration database. Before
you deploy the DCM, you will need to configure it for your needs, either using
its on-board Web server or over a direct serial link.
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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.
• The mgetty-r service is similar, but is more suited for serial links
including modems, in which the link is not always active. This is the
default option.
• Any of the serial ports on the DCM can be directed to transmit GCF
(Güralp Compressed Format) data by setting the serial.x.service option
for that port to gcf_out. You can then run Scream! or other software on
your computer to receive the data. You will not be able to access the
Web configuration interface using this service, although you may be able
to configure attached digitizers from Scream!.
• Likewise, any serial port can be set to listen for incoming data (e.g. from
a connected digitizer or another DCM) by setting the serial.x.service
option to gcf_in. The DCM will automatically combine this data with
any other streams it is receiving, and send it on using all gcf_out ports
and any other transmission methods which have been configured.
• You can log in to the Linux operating system over a modem link by
setting the serial.x.service option to mgetty. mgetty listens for incoming
calls from your computer and sets up a login session for you. You may
need to configure minicom or hypertrm to communicate with your
own modem before you can do this.
• Both mgetty and mgetty-r can recognize incoming PPP connections and
will automatically run a PPP daemon if you attempt to connect to the
DCM in this way.
Network services
Because the DCM is a fully-fledged Linux machine, you will need to set up
networking before you can use it. Advanced networking is beyond the scope of
this manual. For a basic setup, you will need to perform the following actions:
1. Assign the DCM an IP address. By default, the DCM will try and use
DHCP (Dynamic Host Configuration Protocol) to find its own IP
address. However, this requires a DHCP server on your network. If you
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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.
• All DCM units feature an on-board Web server, which allows you to
monitor and configure the station from any browser (and download data
by HTTP, if enabled.)
• For maintenance, you can log in to the operating system directly over the
secure shell protocol, SSH, and use all the standard Unix/Linux tools.
• A GCF server can be set up to transmit data to any application that
supports the GCF format (such as Scream!, Antelope, or Earthworm.)
• The DCM can act as a CD1.0 or CD1.1 transmitter to a specified client,
or to multiple clients as an option.
• Optionally, the DCM can also receive and process AutoDRM messages.
In addition, the DCM can be configured to act as a data client, receiving GCF
and CD1.0/1.1 data streams, combining these streams and storing or
retransmitting them as appropriate. See Chapter 3, “Usage” for full details.
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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. If you are going to use the DCM as part of a TCP/IP network, you must
set up its IP address and other networking parameters before you can
connect to it. Whilst the network is inoperative, you will need to connect
to the DCM console over a direct serial connection. We recommend that
you configure the DCM correctly, to the best of your knowledge, before
shipping it into the field.
3. If you want to connect to the DCM using TCP/IP over modem links, you
must set up PPP over these links. Configuring PPP is beyond the scope
of this manual: please see the Linux man page for ppp for details, or the
Linux PPP HOWTO.
4. Once communication with the DCM is working, you should set up the
serial ports on the DCM to provide the services you require.
5. When all ports are configured, you can use the DCM to set up attached
Güralp digitizers and digital instruments.
2.2 Power supply
The stand-alone DCM receives its power from lines in its data connectors. All
three of these ports are Güralp standard 10-pin combined serial/power
interfaces. Cables are available from Güralp Systems which enable you to
connect a 9-pin D serial interface and 2-way power connector to any of these
ports.
You can power the DCM from whichever data port is most convenient, whether
or not it is being used for receiving or transmitting data. However, you should
always supply power to the DATA OUT plug if possible, since it is easy to
accidentally short the pins of a male connector. Attached digitizers and sensors
are powered from the same supply as the DCM. Any 12 V DC power supply
may be used; if using batteries, we recommend that you use a unit with lowvoltage disconnect to avoid excessive drain.
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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. See Appendix A, “Connector pinouts” for the positions of these pins.
2.3 Connecting to a single computer
In autonomous or temporary installations, you will only need to connect the
DCM to one computer (e.g. a laptop) for initial configuration. Follow these
instructions to make the DCM communicate with your computer.
Note that your computer must either have an RS232 (serial) port for initial
connection, or be running its own DHCP server. DHCP servers are available for
Windows, but are not supplied as standard.
If you want to connect the DCM to a local area network, follow the instructions
in Section 2.4, “Connecting to a local network” instead.
Connecting over a serial link
The DATA OUT port can be used to connect a DCM to a single computer
through a direct serial link. This link can be used to log in to the Linux
operating system of the DCM and transfer files. It is most useful for
maintenance and troubleshooting over a low-bandwidth connection, and for
initial setup.
To communicate over a serial link:
1. Connect an RS232 reverse serial cable between the DCM and your
computer. A suitable cable should have been supplied with the unit.
2. Run a terminal emulation program on the computer. The built-in
programs minicom for Linux, and hypertrm for Microsoft
Windows, can be used for this.
3. Configure the baud rate of the serial link. By default, the DCM uses a
baud rate of 115200, with 8 data bits, no parity bit, and one stop bit, and
without flow control.
4. Log in with your username and password, or root if you have not yet
created one. See http://www.faqs.org/docs/Linux-
HOWTO/Text-Terminal-HOWTO.html for full information on
how to set up terminal emulation under Linux.
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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. This has the same effect as connecting the DCM and your computer
to a separate hub using standard Ethernet cables: the two machines will
consitute a network segment, and each will have its own IP address on that
segment. See Section 2.4, “Connecting to a local network” for details on how to
configure TCP/IP on the DCM.
If your computer has two network interfaces, and one is connected to a local
area network, you may be able to set up a network bridge between the DCM's
segment and the rest of the network. For example, if you are using Microsoft
Windows XP:
1. Connect to the DCM's console over a serial link.
2. Because you are connecting the DCM to a single computer, you will
probably not be able to use DHCP. You should configure the DCM to
disable DHCP and use an IP address in a private range such as
192.168.0.x:
gcfgdbset net.eth.0 static
gcfgdbset net.eth.0.address 192.168.0.2
gcfgdbset net.eth.0.netmask 255.255.255.0
Here, 192.168.0.2 should be replaced with the IP address you want
the DCM to use.
Allow a short time for the DCM to reconfigure the network.
3. On your computer, select Start Control Panel Network→ →
Connections. Right-click on the interface connected to the DCM, and
select Properties.
4. Click on Internet Protocol (TCP/IP), then Properties.
5. Select Use the following IP address, and fill in an address on the same
subnet as the DCM (e.g. 192.168.0.49). Click OK, then OK in the
Connection Properties window.
6. Check that you can connect to the DCM using its new IP address by
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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.
To set up the bridge, open the Network Connections window, and select
the connections corresponding to the DCM and your network. Click
Bridge connections, and follow the instructions in the wizard.
If you are using Linux or another operating system, you should see its own
documentation for more details.
Using an internal modem
If you have ordered a DCM with an internal PCMCIA modem, it will
automatically listen for incoming PPP connections. This is most useful if the
DCM is integrated into a borehole instrument, which can then be connected to a
modem at a central data collection point. The modem within the DCM appears
on the Web configuration interface as a serial port, allowing you to change the
service it provides and the data transfer settings it uses. For example, if you do
not want the internal modem to use PPP, you can configure it to use mgetty
instead and log in directly.
Connecting over USB
If your DCM is equipped with the USB client interface, you can connect it
directly to any computer with a USB socket. When this is done, the computer
treats the module as if it were a standard network card. For example, to connect
the DCM to a PC running Microsoft Windows, you should:
1. Link the DCM's USB port to any available USB socket on the computer.
2. After a short wait, Windows should report that a new USB device has
been detected. When prompted to install drivers for it, you should use
the ones provided on CD by Güralp Systems.
Once the “network card” is installed, the two machines will consitute a network
segment, and each will have its own IP address on that segment. See Section
2.4, “Connecting to a local network” for details on how to configure TCP/IP on
the DCM. If you wish, you can set up a network bridge between this connection
and a local area network or the Internet as described above.
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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. Otherwise, you will need to connect to the DCM over a serial link to
find out its IP address.
If you do not use DHCP on your network, you will have to set the DCM to use a
static IP address.
1. Make a temporary serial connection to the DCM from a local PC. You
should see the message
DCM login:
2. Enter root and the administrator password. If you have not been given
a password, the default setting is rootme. The DCM will reply with a
prompt:
[root@DCM ~]#
This verifies that the unit is working properly. You should change the
password as soon as you can with the command passwd
3. Connect the DCM's NETWORK port to your network, and power cycle
it. Log in again.
4. If your network does not use DHCP, type
gcfgdbset net.eth.0 static
to make the DCM use a static IP address instead, and set the address
with
gcfgdbset net.eth.0.netmask 255.255.255.0
gcfgdbset net.eth.0.address your-address
Here, your-address should be replaced with the IP address you want
the DCM to use. The IP address you choose must be unique on your
network.
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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. The NETWORK port uses the
interface eth0:
eth0 Link encap:Ethernet HWaddr 08:00:20:C0:FF:E2
inet addr:192.168.48.187 Bcast:192.168.48.255
Mask:255.255.255.0
UP BROADCAST NOTRAILERS RUNNING MULTICAST
MTU:1500 Metric:1
RX packets:88045 errors:36 dropped:0 overruns:36
frame:0
TX packets:16308 errors:0 dropped:0 overruns:0
carrier:0
collisions:149 txqueuelen:100
RX bytes:12358214 (11.7 MiB) TX bytes:0 (0.0 B)
Interrupt:76
If the interface is correctly set up, its IP address will be shown after
inet addr: (here, 192.168.48.187.)
6. If you are connecting the DCM to a single computer which does not run
a DHCP server, you will need to configure that computer to use an IP
address on the same subnet as the DCM before they will be able to reach
each other (see “Connecting over Ethernet” in Section 2.3.)
You should now be able to connect to the DCM's Web setup interface by typing
its IP address into any browser, e.g.
https://192.168.0.2/
Scream! and similar software applications should also be configured to use this
address to communicate with the module, if they are intended to communicate
over the network.
Alternatively, you can continue using the gcfgdbset command to set other
configuration options by name. In Chapter 4, “Configuration options”, each
option's name is given in italics. The command syntax to use is
gcfgdbset option-name new-value
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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 802.11 network may operate:
• In ad hoc mode, data packets are sent out over the wireless connection
indiscriminately and are received by all machines on the network. This is
the simplest style of Wi-Fi network, but consumes more power and
cannot easily be extended to large networks.
• In infrastructure mode, dedicated 802.11 hubs collect data packets,
collate, and distribute them efficiently around the network. These hubs
may also act as transparent extensions to existing (wired) TCP/IP
networks.
The DCM is capable of running in either situation, depending on your
requirements. As far as the computers on the network are concerned, there is no
difference between a TCP/IP network running over Ethernet and one using
802.11 connections, or a mixture of the two.
Once the 802.11 system is running, you will need to run a DHCP service on
your network, or manually set the IP address of the DCM as above.
Connecting to the Internet
If the local network is already connected to the Internet through some other
means (perhaps through a gateway machine), you can create a default route with
gcfgdbset net.eth.0.gateway network-gateway
where network-gateway should be replaced with the IP address of the
gateway on your local network.
The DCM can perform more complex routeing if required. See “Static routes”
in Section 4.4 for more details.
As supplied, the DCM module will accept requests to its on-board Web server
and logins over SSH. In addition, the DCM can be requested by Scream! or
other GCF-compatible software to send GCF streams to your computer.
If the instrument is located on a private network, you may be able to connect to
it from the wider Internet by using a feature implemented by SSH known as
tunnelling. You can use this technique to connect to the DCM through a chain
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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.
2.5 Connecting digitizers and external hardware
The DCM is designed for use with Güralp Systems digitizers, which
communicate over RS232 or RS422 serial links using the GCF protocol. There
are three RS232 ports available on a stand-alone DCM and ten on a rackmounted model, whilst on a DCM bonded to a digitizer unit only the DATA
OUT port is available (the digitizer is connected directly to the PORT A
interface).
The three serial ports on a stand-alone DCM are labelled DATA OUT, PORT A,
and PORT B. In a typical setup, one or both of the latter two ports are connected
to Güralp DM-24 digitizers, whilst the DATA OUT port connects the DCM to a
computer or serial modem. However, the labels are provided merely for
convenience: internally all three serial ports behave identically. Thus, if the
DCM is connected to a network over Ethernet, you could use all three ports to
communicate with digitizers. Conversely, if you have only one digitizer
attached to a stand-alone DCM, either or both of the remaining two ports could
be used to transmit data gathered by the module.
A rack-mounted DCM has a CONSOLE port with a female connector,
corresponding to the Data out port of the stand-alone model, and nine serial
ports (with male connectors) for communication with digitizers. These appear
on the Web configuration interface with their Linux device names /dev/ttyS0,
S1, etc., up to S7. The TTY port corresponds to /dev/ttySB0, whilst the
CONSOLE port is shown as /dev/ttySA0.
If the DCM has a USB host interface, you can connect it to any USB peripheral
supported by its Linux operating system. For example, you may want to attach a
camera to the DCM, or an additional USB mass storage device. If there is no
hard disk inside the module, it will automatically search for suitable storage on
the USB interface. The DCM may alternatively have been supplied as a USB
client; if this is the case, the USB connection can be used to connect the module
to a single computer (see below).
2.6 Setting up the CMG-DCM
Once a DCM is installed, it must be configured to your particular requirements.
The principal way to set up a DCM is through its on-board Web server, which
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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. For example, if the DCM has the
address 10.82.0.1 you would enter
http://10.82.0.1/ or https://10.82.0.1/
https is a secure variant of the http protocol, which ensures that network traffic
cannot be read in transit. The DCM as supplied accepts connections only over
https, although this may be altered if required (see “HTTP server” in Section
4.5)
Your browser may ask you for a username and password to access the Web
configuration interface. An initial root username and password will have been
supplied by Güralp Systems; however, you should check with the DCM's
administrator what username you should use. On a clean install of the Linux
distribution, the password for root is rootme.
Once you have logged in, you will see a Web page similar to this:
The work area on the right displays a summary of the DCM's current state,
including a report on network traffic (produced by the Linux ifconfig
command), details on the services provided by its internal serial ports, and
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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. If you want to add any other
named accounts, you may do so at this stage (see “Administrators” in Section
4.4)..
At this point, you should configure the DCM for your own needs. Examples of
how to configure a DCM for several common applications are given in Chapter
3, “Usage”, whilst a full reference is provided in Chapter 4, “Configuration
options”. Some important points to note are:
• The DCM uses internal serial and Ethernet ports to communicate with
the digitizer and the network. Altering the settings under Serial port
configuration or Network configuration may make the DCM
unreachable over the network. You should review carefully any changes
you make to these settings before committing them.
• You can disable the DCM's ssh, http, and https servers using the links
under Data transfer. Before doing this, you should ensure that you will
still have access to the DCM by other means, e.g. by logging in directly
over ssh.
Setting up digitizers
You can change the configuration of attached DM24 digitizers through the
DCM's web page interface. To do this, click on Digitizer Setup beneath Actions
in the menu tree. The DCM will then retrieve the current configuration from the
DM24, which will take a few seconds. This done, a page will appear allowing
you to alter the digitizer's settings:
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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”.
The initial digitizing process outputs data at a rate of 2000 Hz, which is
decimated at Tap 0 by a fixed factor of 10. You can control which data streams
the digitizer outputs at this point using the top row of the first grid of Z, N, and
E checkboxes on this page. Subsequent grids of checkboxes determine which of
the other taps output data. For example, you could output the Z component at
200 Hz, together with all three components at a lower rate.
You can also set trigger criteria for the digitizer. The criteria can be applied to
any component at any tap, and as soon as they are satisfied, any component with
a checked box in the lower (triggered) row of one of the grids will begin
outputting data in addition to the normal streams. You cannot have the same
component produce both triggered and continuous output at the same tap.
See “Digitizer output control” in Section 5.2 for full details of what you can do.
Using Scream!
If you prefer, you can use Güralp Systems' Scream! software to configure and
calibrate digitizers and sensors through the DCM module, just as if they were
connected directly. For full details on how to use Scream!, please refer to its
own documentation or the extensive on-line help.
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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. For full configuration information, please refer to Chapter
4, “Configuration options”.
3.1 General notes
Stand-alone DCM modules can be supplied with a touch-screen and
minibrowser as an option. This allows you to perform configuration tasks onsite. However, the touch-screen imposes some environmental restrictions on the
unit.
For all other DCM units, you will need console or network access to the DCM
to configure it for your installation. This is especially important if the DCM is
not to be part of a TCP/IP network whilst in use. As supplied, the DATA OUT
port runs the getty service, which you can use to access the console of the DCM
over a serial link. Alternatively, you can temporarily connect a computer to the
NETWORK port. It is recommended that you keep a connection to the DCM
available for maintenance and troubleshooting, even if the link is too slow for
transferring data.
3.2 The DCM as a data store
The simplest way to use a DCM is as a storage medium for digital data.
1. Connect the DCM to a digitizer or digital sensor.
2. Connect the DATA OUT port to a source of 12 V DC power.
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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.
Data is stored in the Flash memory as a number of files in Güralp
Compressed Format (GCF) unless you have specified another option.
Once the memory becomes 75% full, files are automatically moved to
the hard disk until it is less than 50% full. (See Section 6.1, “File
systems” for details of the algorithm used.)
You can check that the DCM is receiving data either by monitoring the
Summary page of the on-board Web interface (see Section 5.7,
“Summary”), or from a command prompt using the command
gnblocks port-number
to find the number of GCF blocks received so far on a port. To see the
number of blocks recorded on all ports, type
gnblocks
5. If the internal hard disk is missing or becomes full, and you have chosen
the USB host option, the DCM will automatically look on the USB
interface for an external USB mass storage device.
6. To replace the internal hard disk, unclip the cover of the DCM and hold
down the lever button to bring the disk out from its housing.
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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.
In Windows XP, you should see a series of Found new hardware
messages indicating that the drive has been recognised. A new disk drive
icon should appear in My Computer:
This process may take several minutes to complete.
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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.
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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. You can do this in addition to
recording data on a local hard disk, or you can leave the hard disk uninstalled
and operate the DCM entirely over the network link.
This example shows a module communicating with a local PC over a dedicated
radio link. You could also use a simple serial cable to connect the DCM to the
PC.
1. Connect the DCM to a digitizer or digital sensor.
2. Connect the DATA OUT port to a source of 12 V DC power.
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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. If you do want to be
able to do this, you should configure the serial link for PPP (see “PPP”
in Section 4.4) and run a Scream! server on the DCM. You will need to
assign the DCM its own IP address on your local network.
5. If you connected to the DCM by PPP, you will lose the network
connection at this point, because the DCM is now using the serial link
directly.
6. Open Scream!'s main window, and look under Local in the tree on the
left for the serial port which is communicating with the DCM. If it is not
shown, you may have to 'unfold' the tree to reveal it. The digitizer(s)
attached to the DCM will appear underneath the entry for the serial port,
and you can configure them from within Scream!. See Scream!'s
documentation for more details.
7. If no digitizer is shown, it may be that your software is not configured
correctly for the serial link. As supplied, the DCM uses a baud rate of
115200 on its CONSOLE port, with 8 data bits, no parity bits and 1 stop
bit, and no flow control.
For more information on how to use Scream! to display and manage data
streams, please see Scream!'s own documentation or the extensive on-line help.
Accessing the DCM command line through gcf_out
The gcf_out service provides a command-line terminal designed to be
compatible with Güralp Systems' SAM serial storage device. To access this
terminal from Scream!, right-click on the DCM's icon and select Terminal....
The SAM commands you can use are described in the SAM Operator's Manual.
You can also log in to the DCM's Linux operaing system through the terminal.
Enter the command
GETTY
and press ENTER. You will be presented with the login: prompt.
If you are not using Scream!, you can interrupt the GCF data stream and drop
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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.
Here, DATA OUT ports with gcf_out as the service output data to the serial
inputs of another DCM or AM module, which aggregates them all and sends
them out over a network connection.
The DCM can handle multiple data sources with ease using the gcf_out service.
In practice, however, it is almost always preferable to set up a local area
network and use PPP over any serial links, so that GCF, Web and SSH traffic
can share the same connection. Setting up a fully networked array is slightly
more involved than using the simple gcf_in and gcf_out services, but affords
much more flexibility. See below for more details.
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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. If your
DCM is a host, you can attach external USB peripherals such as hard
disks. If it is a client, you can attach it to a computer, and it will appear
as a network interface.
3. Connect a Güralp combined serial/power cable to the DATA OUT port.
Make up a connector if necessary, and attach the power lines to a 12 V
DC power supply.
4. Connect the 9-pin serial socket to a computer for configuration.
5. Connect an Ethernet cable to the NETWORK socket, and set up the
network as described in Section 2.4, “Connecting to a local network”.
You should now be able to connect to the DCM's Web setup interface by typing
its IP address into any browser, e.g.
https://192.168.0.2/
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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!.)
The DCM also runs a SSH (secure shell) server, which you can use to access its
Linux command line over the network, just as if you had connected to it over a
direct serial link. The standard Linux program ssh and the freeware Windows
program putty are popular SSH clients.
If you do not wish to use the DCM's Web site, you can continue using the
gcfgdbset command to set other configuration options by name. For the
option names, you should refer to Chapter 4, “Configuration options” in the
DCM manual, where each name is given in italics with a description of its
action.
The command syntax to use is
gcfgdbset option-name new-value
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.
Communicating with digitizers
From the DCM, you can connect to the console of attached digitizers with the
command
minicom -n port-number
Alternatively, you can send individual commands to a digitizer with the
command
gcli port-number command
In these commands, port-number is the port number and port-name the
port device name to send the command to. To find out these, issue the
command serialmap:
Library version: libserialmap Version 1.0.5 with LIBGCONFIGDB
3 serial ports
Port 0, Key 7000, name Data out port, device /dev/ttySA0, baud
115200
Port 1, Key 7001, name Port B, device /dev/ttySA1, baud 9600
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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. You can change all of the digitizer's configuration options from this
page. If you have attached a 6-channel digitizer, the page will reflect
this:
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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. The time period used can be configured from the Disk
menu of the DCM's Web site.
You can list the files on the hard disk
• over the Web, by selecting Disk files from the menu, or
• from the command line with gfat32 ls
If you are using the Web page interface, each file appears as a link: simply click
its name to download the file.
Alternatively, you can remove the internal hard disk physically, and attach it to
any computer supporting either Firewire or the USB Mass Storage Protocol. It
will appear on the computer as an extra hard drive. The DCM uses a journalling
file system compatible with Windows' FAT32, so you cannot lose or corrupt
data by removing the hard disk, even if the DCM is in the middle of writing to
it.
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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.miniseed option using the Disk page of
the Web site:
The DCM allows you to record in several formats simultaneously, if you wish;
you should make sure that you have the capacity to store, or the bandwidth to
transfer, all the data the DCM will produce in each format you have enabled.
Compiling SEED volumes
The DCM can also compile full SEED volumes in real time. To enable this, use
the command
gcfgdbset disk.recordas.seed yes
or select yes for the disk.recordas.seed option on the Disk page of the Web site.
Before the DCM can start writing SEED volumes, however, it needs to know
technical details for each stream you wish to record. To set these, navigate to
the Data Transfer SEED → page of the Web site and edit the
/etc/seed.cfg file. The DCM will only write SEED volumes for streams
mentioned in this file. See “SEED” in Section 4.5 for more details.
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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.
• By default, the DATA OUT port runs the getty service, which allows you
to connect to the DCM's console.
• The mgetty and mgetty_raw services are similar, but can deal with
connections made through modems.
• The gcf_out service causes the DCM to combine the incoming GCF
streams and send them on transparently, as for a Güralp SAM or CRM.
• The gcf_in service turns the port into an extra digital data input port. The
DCM's PORT A and PORT B run the gcf_in service.
Scream! server
In a straightforward vault installation, we recommend that you leave the DATA
OUT port running the getty service for emergency console access, and instruct
the DCM to act as a server for incoming data on your network. This can be done
from the Data transfer → Scream! Server → page on the Web site:
1. Enable the Scream! server on the DCM by setting
datatransfer.scream.server to on and
datatransfer.scream.server.allowserialaccess to yes. Make a note of the
port number datatransfer.scream.server.port, or change it to another.
Click Save settings.
2. Start up Scream!, and select Windows Network Control... → from the
main menu. Click the My Client tab.
3. If it is not already selected, check Receive Data to start Scream!
listening.
4. Right-click anywhere in the Servers list box, and select Add UDP
Server.... Enter the IP address and port number of the DCM, separated
by a colon : (e.g. 192.168.0.2:12345)
5. Test communications by right-clicking on the newly-added server, and
selecting GCFPING. A message appears in the Control pane logging
the ping being sent. If communication is good, and the server is enabled
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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. If you do not GCFSTOP, the server will continue to
transmit to a client that is no longer listening. You should ensure that the
server replies with a GCFACKN message If an acknowledgement does
not appear in the Control pane, repeat the GCFSTOP command.
CD1.0 and CD1.1
The DCM can be configured to transmit incoming data to a specified client
using the CD1.0 or CD1.1 protocols. If you intend to send CD1.0 or CD1.1 data
to a National Data Centre (NDC), the installation will need to be assigned a
unique code by the International Seismic Centre or with the US's National
Earthquake Information Center.
To enable CD1.0 or CD1.1 transmitters, scroll down to Data transfer and select
CD1.0—Transmitter or CD1.1—Transmitter. Fill in the required data fields and
click Save settings. The meaning of each field is explained on the page and in
Chapter 4, “Configuration options”.
Using an Authentication Module (AM) you can cryptographically sign all
outgoing CD1.0 or CD1.1 subframes as they pass through. This is particularly
powerful where the module is physically part of the sensor casing, as it allows
you to generate authenticated data at source, even within a borehole.
Optionally, the DCM can also accept CD1.0 or CD1.1 data from another
instrument. Incoming data is stored in Flash memory, just like that coming from
attached sensors, and can be retransmitted as CD1.0, CD1.1, GCF, or by any
other method as required.
AutoDRM
AutoDRM (Automatic Data Request Manager) is an optional service which
allows you to request data over e-mail. In response to a request, the AutoDRM
can either send an e-mail in return, or establish an FTP connection to you.
In order for the AutoDRM system to work, the module must be able to send and
receive e-mail messages. To set the system up, you will need to fill in the details
of your network's SMTP server under Outgoing mail setup, and of your POP or
IMAP server under Incoming mail setup. Remember to click Save changes after
you have filled in each screen.
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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.DCM should be replaced with an e-mail address
which will be delivered to the autodrm mailbox on the DCM.
The DCM should send a mail back to you containing help on the commands
you can give the AutoDRM.
3.5 Troubleshooting DCM installations
I cannot connect to the DCM's DATA OUT port using a terminal program.
Press ENTER a few times to initiate communication.
If the DATA OUT port gives a login prompt, you should log in with your
username and password. If you have not been given a different username and
password, try logging in as root with the password rootme. You should
change this password as soon as you can with the command passwd
If the DATA OUT port gives an ok prompt, the DCM is running the gcf_out
service on that port and has provided you with a FORTH compatibility
interface. Type
GETTY
and press ENTER to gain access to the login prompt.
If the DATA OUT port does not respond when you press ENTER, or produces
garbage, check that your terminal program is using the same baud rate as the
DCM. By default, the DCM uses a baud rate of 115200, with 8 data bits, no
parity bit and 1 stop bit, and no flow control.
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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 255.255.255.0
gcfgdbset net.eth.0.address 192.168.0.2
(replacing 192.168.0.2 with the IP address you want the DCM to
use.)
• If the DCM is using DHCP, use ifconfig to verify that the DCM is
using the IP address you expected. If it is not, change the settings of your
DHCP server or connect to the correct IP address for the DCM
• Check that your local PC can route to the DCM's IP address. For
example, if you are using a cross-over Ethernet cable, the two hosts must
share a subnet.
• Check that the DCM's HTTP(S) server is enabled by issuing one of
gcfgdbset net.remoteaccess.allow.http yes
gcfgdbset net.remoteaccess.allow.https yes
as necessary.
I cannot connect to the DCM's Scream! server.
Make sure you are using UDP to connect to the DCM. Scream! servers between
computers (including the DCM) always use UDP. The Add TCP server...
option in Scream! is intended for hardware serial-to-IP converters only.
I cannot GCFPING the DCM's Scream! server.
• Check the Receive UDP data checkbox in Scream!'s Network Control
window.
• Open the DCM's Web site, and check that the option
datatransfer.scream.server is set to on, and that
datatransfer.scream.server.port is the port you expected.
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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.
If you do not want to use the DCM's Web site, you can find out the number of
GCF blocks the DCM has received with the command gnblocks. Each serial
port will be listed, with its name, number, key number and device name (as for
serialmap) but including the number of blocks received on that port:
Key 0x007005: Blocks 3287 (Port 5, name Port A (COM6),
device /dev/ttyS2, baud 9600)
The DCM is not receiving any data streams.
• Check the connection between the digitizer and the DCM by trying to
log in to the digitizer's console using any of the methods described in
“Communicating with digitizers” in Section 3.4. Press ENTER a few
times to initiate communication.
• If the digitizer gives an ok prompt when you press ENTER, check that
you have configured the digitizer to output real time data streams.
Streams will not appear until a whole GCF block (1024 bytes) is ready
for transmission, so a 5 sps stream may not appear until the digitizer has
been working for 4 minutes. In addition, you can configure a digitizer to
output only triggered streams, in which case it will not appear until a
trigger occurs. (There is an exception to this: if you have put the
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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. To change the DCM's settings,
exit the terminal program, and either
• use the Serial port configuration → port name Web page, or
• issue configuration commands such as
serial.5.service gcf_in
serial.5.baudrate 9600
serial.5.handshaking none
To obtain the port number (here 5) corresponding to a named port, issue
the command serialmap.
• If the digitizer is not responding at all, check the power supply to the
digitizer and the cable between it and the DCM.
The DCM is receiving streams, but they do not contain any data.
If the data you see is zero:
• Increase the Y axis scale using the icon in Scream!'s
Waveview window or the corresponding icon in the DCM's Data Viewer.
• Check the mass position outputs to see if the masses are locked. A
properly unlocked and centred mass should show a mass position within
1000 counts of zero; a locked mass will give a value in the region of
32,000 or 32,000 counts. If your sensor has remote mass locking, you−
can unlock the masses by navigating to Actions Digitizer setup → and
clicking Unlock sensor.
Locking or unlocking the sensor mass typically takes several minutes to
complete.
• Check the connection between the sensor and digitizer and try again.
If you cannot see the data in the stream, remove any constant offsets by clicking
on the Zero streams icon in Scream!'s Waveview window or the DCM's
Data Viewer.
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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.
If you are using triggered output streams, be especially careful to allow a high
enough baud rate to transmit data from all possible output streams
simultaneously, or you will observe gaps when an event triggers the digitizer.
The DCM receives streams, but 2-minute gaps appear in the data at 4-hour intervals.
After a reboot, the DCM takes around 2 minutes to begin transmitting. The
DCM runs a guardian process which monitors the health of the system. In
some circumstances guardian will need to reboot the DCM to attempt to
resolve a problem. If the reboot does not help, the DCM will soon find itself in
the same position, and guardian will reboot it again.
You can check the time since the last reboot with the command uptime, which
will respond with a line like
14:30:32 up 34 min, load average: 1.24, 1.32, 1.10
In this example, the DCM last rebooted 34 minutes ago.
The most common circumstance where guardian will reboot a DCM is when
the operator has instructed it to record data, but it cannot do so, either because
• the Flash memory is full, and all connected USB disks are also full,
• the Flash memory is full, and no USB disk is present; or
• the Flash memory is full, and a USB disk is inaccessible for some other
reason (e.g. it is unformatted, incorrectly partitioned, or faulty).
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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. Once you have changed settings on any
page, you should click Save changes at the bottom of the page for the DCM to
make your new choices active. If you move to a different page without saving
the settings, your changes will be lost.
To change the configuration of the digitizer(s) and instrument(s) attached to the
DCM, you should use the Actions Digitizer Setup → page (see Chapter 5,
“Actions”.)
Note: The DCM is a highly flexible unit, which can be supplied with a range of
feature sets depending on your requirements. A stand-alone DCM unit normally
has most of these options available to the user. However, some of the settings
described below may not be relevant to your installation, and thus will not be
available.
Conversely, a DCM may be supplied which supports multiple instances of a
particular service (e.g. several CD1.1 transmitters.) In this case, each instance
will have its own configuration page, which will appear as described below for
that service. Users of installations which include several types of DCM or AM
(Authentication Module) will find that each unit offers a different range of
configuration options, according to its specialization as a component in the
system.
In this chapter, the name of each setting is marked in italics. This name is
shown on the Web page interface, and can also be used to access the setting
using the gcfgdbset command (see Section 6.2, “Command line tools”.)
4.1 General
This page contains a single setting.
general.hostname : This is the host name the DCM will use to identify itself. It
is normally the first part of the module's fully-qualified domain name, for
example, a DCM at myinst.bignet.org would have its host name set to myinst.
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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. The latter two are
provided for archival purposes, and are not optimised for data transfer; Güralp
digitizers and software all work natively with GCF, the Güralp Compressed
Format. The DCM allows you to record in several formats simultaneously, if
you wish; you should make sure that you have the capacity to store, or the
bandwidth to transfer, all the data the DCM will produce in each format you
have enabled.
One file will be prepared for each format (or format and stream, for those
formats which deal with single streams) every three hours. The DCM will
always start a new file if it is power cycled; the aborted file will still be valid.
Files are not immediately written to the disk, but into Flash memory; the
options disk.usagemode and disk.writeinterval, below, control how often the
DCM flushes new data to the disk, and what it will do if the disk becomes full.
disk.recordas.gcf : Set this to yes to have the DCM record Güralp Compressed
Format data files.
disk.recordas.miniseed : Set this to yes to have the DCM record files in
miniSEED format.
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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. Select yes to have the DCM record data coming into this
port.
disk.recordfrom.scream : Select yes to have the DCM record data it receives
from remote Scream! servers (either computers running Scream!, or further
DCMs and AMs.) If you want to use this option, you should also configure the
datatransfer.scream.client options (see below.)
disk.recordfrom.http : Select yes to have the DCM record data it receives using
the HTTP protocol. If you want to use this option, you should also configure the
datatransfer.http.client options (see below.)
disk.recordfrom.cd1_0 : Select yes to have the DCM record data it receives
using the CD1.0 protocol. If you want to use this option, you should also
configure the datatransfer.cd1_0 options (see below.)
disk.recordfrom.cd1_1 : Select yes to have the DCM record data it receives
using the CD1.1 protocol. If you want to use this option, you should also
configure the datatransfer.cd1_1 options (see below.)
disk.power : To save power, the on-board hard disk can be set to power up only
when required. If power consumption is an issue and you expect the hard disk to
be used only occasionally, you should set this option to automatic. Otherwise,
setting it to always-on will ensure that the hard disk is always ready to receive
data. If you intend to operate an internal disk continuously, you should take care
not to let it overheat, since the interior of the DCM is well insulated.
disk.usagemode : This setting varies the way the DCM uses its hard disk storage
once it has been filled up.
• The use-once option causes the DCM to stop recording data to the hard
disk, and discard any new data that arrives. It may still send new data
over the network, if you have so configured it, but the hard disk will be
untouched once full. Thus the start point of the stored data is known, but
the end point depends on the disk capacity. This is most useful for
installations where you are expecting to replace the hard disk
periodically, or where you need to take time-synchronized readings at
several sites.
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• 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. There is also an automatic setting available, in which data will
be written out to the hard disk whenever the DCM's internal memory nears
capcity. (See Chapter 6, “Inside the DCM” for details of the algorithm used.) If
you choose one of the manual timescales for this option and the DCM runs out
of internal memory, you may lose data: as a result, it is recommended that you
leave this setting on automatic.
disk.heater : A heater is provided in the internal enclosure of the DCM to bring
the on-board hard disk up to operating temperature when required. If you are
using an on-board hard disk, you should set this option to automatic and choose
a suitable operating temperature below. If you are not using an internal hard
disk, you should disable the heater by setting this option to off.
disk.temperature : The operating temperature of the on-board hard disk, in
degrees Celsius. If you have set the internal heating to automatic, you should
enter a suitable operating temperature here. The hard disk will not function
properly below 0°C. With the heater active, the DCM is designed to operate in
ambient temperatures up to 40 degrees below zero.
4.3 Serial port configuration
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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). The
configuration options for all the ports are as follows:
serial.x.baudrate : This option alters the speed of communication across each
serial link, in bits per second.
For ports connected to digitizers, you should ensure that the baud rate is high
enough to allow all the data to be transmitted at the rates you have chosen. As
an example, for three streams transmitting at 100 Hz, a rate of 9600 baud is
usually sufficient. Modern modems can normally operate at rates up to 57600
baud (~56 kbits/s), although the telephone or transmission lines may not support
such a high rate. The same is true of radio telemetry links.
The DCM's serial ports operate using frames of 8 data bits, no parity bits, and
one stop bit.
serial.x.device : The pathname of the Linux device corresponding to this serial
port. You should not need to change this option.
serial.x.handshaking : The flow-control (handshaking) protocol used across
each serial link. There are three options:
• off : Transmit data across the serial link without handshaking, i.e.
assume that the link is always ready to send or receive data.
• rts/cts : Use the Ready To Send/Clear To Send handshaking method,
where two separate lines within the serial cable are used to control the
flow of data. This is the most reliable method since accomplished in
hardware, but is not feasible for long-distance or complex connections.
• xon/xoff : Send the two special characters ^Q (17) and ^S (19) as part of
the data stream to request that data transfer be started and stopped. This
method requires only a single connection, but assumes that the special
characters will be received correctly every time.
serial.x.name : The name of this serial port. You should not ordinarily change
this setting.
serial.x.ppp : You can use any of the serial ports to establish a network
connection with a computer using the PPP protocol by setting the
serial.x.service option, below, to ppp. The DCM uses the standard Linux
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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.service : How the DCM will use each serial port. There are five options:
• getty : The module will use this port to listen for logins from a
connected computer. Once logged in, the user will have direct
command-line access to the DCM's Linux operating system.
• mgetty : The module will use this port to listen for logins over a
connected serial modem. Again, a logged-in user will be presented with
the DCM's Linux command line.
• mgetty-r : The module will use this port to listen for logins over a
connected serial modem which is operating in raw mode (i.e. which does
not support the standard AT modem commands.) This option in runs the
Linux command mgetty -r. A port running the mgetty-r service will
also listen for incoming PPP frames, and if it detects one will configure
the PPP link according to the
/etc/mgetty+sendfax/login.config file (see “login.config”
in Section 4.4.)
• ppp : The module will use this port to provide a PPP link to a connected
computer. Once set up on the computer, the DCM will appear as if on a
local TCP/IP network. You can then log in to it using ssh or use its
Web-based administration system, as well as receiving data.
Before a PPP link will function, you will need to specify the PPP options
and (if using CHAP) provide a chap-secrets file. This can be done
through the DCM configuration interface: see “options” in Section 4.4
and “chap-secrets” in Section 4.4. Also see the Linux manual page for
pppd(8) for an explanation of how PPP is implemented.
• gcf_in : The module will use this port to communicate with a GCF-
compatible digitizer.
• gcf_out : The module will use this port to send GCF data directly to the
connected device as it is received. A number of programs are available
for PCs which handle incoming GCF data streams, such as Scream!,
Antelope, and Earthworm. The DCM transparently merges all incoming
data streams, so if you are using Scream!, you can also configure and
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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.0 and refer to the wireless LAN rather
than to Ethernet networking. They are otherwise identical.
net.eth.0 : If you know the IP address the DCM is going to use over this
interface, you should set this option to static and fill in the details below.
Alternatively, you can select dhcp/bootp and have the DCM automatically
request an address over the network. If you choose the dhcp/bootp option, you
should ensure that a gateway computer exists on your network that can receive
these requests, and that the DNS (nameserver) entry for the DCM is kept
current. You can then ignore the remaining settings on this page.
net.eth.0.address : If the above option is set to static, you should fill in the IP
address of the interface in this box. Valid IP addresses consist of four numbers
between 0 and 255, separated by periods. If you intend to attach the DCM to a
private network, you should use an IP address in one of the private ranges
(10.b.c.d; 172.16-31.c.d; 192.168.c.d) to avoid clashing with addresses on the
wider Internet.
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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. A DCM with an IP
address in the domain 192.168.1.x would normally use a network address of
192.168.1.0.
Static routes
In addition to the standard IP routing mechanisms, you can define up to 4
additional static routes from the DCM to other parts of the network. These
routes are specified as arguments to the standard Unix route command. For
example, if you wanted the DCM to route traffic to and from IP addresses
beginning 192.168.0. over the eth0 interface, you would include the line
add -net 192.168.0.0 netmask 255.255.255.0 dev eth0
in the list.
For more information on the route command, please see its Linux manual
page.
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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. You should give the domains to search in their
correct order, separated by commas. The DCM's own domain (as given in the
net.dns.domain setting) will always be searched first, so you need not specify it
here.
net.dns.server.0 : The IP address of the primary nameserver used to resolve host
names. If you are using dhcp/bootp, the DNS service is negotiated
automatically, and so this setting may be ignored.
net.dns.server.1 : The IP address of the secondary nameserver. Again, you may
be able to ignore this setting if you are using dhcp/bootp.
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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. This
generally depends on the protocol used to retrieve mail:
• For pop3 mail, this port will normally be 110, or 995 for secure POP3
over TLS.
• For imap mail, this port will normally be 143, or 993 for secure IMAP
over TLS.
net.mail.in.server : The hostname or IP address of the mail server.
net.mail.in.tls : Select yes to encrypt the incoming mail channel with TLS, no to
leave communications unencrypted.
net.mail.in.type : Select pop-3 or imap to use that protocol to retrieve mail from
the server. If you do not need the DCM to be able to receive mail, select None.
net.mail.in.username : The username needed to log in to the mail server.
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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.authsmtp : Select yes and give a username and password in the
fields below to use authenticated SMTP for outgoing mail.
net.mail.out.password : The password needed to log in to the outgoing mail
server, if using authenticated SMTP.
net.mail.out.server : The hostname or IP address of the outgoing mail server.
net.mail.out.tls : Select yes to encrypt the outgoing mail channel with TLS, no
to leave communications unencrypted.
net.mail.out.type : Select smtp to use that protocol to send mail to the server.
Currently only SMTP is supported. If you do not need the DCM to be able to
send mail, select None.
net.mail.out.username : The username needed to log in to the outgoing mail
server, if using authenticated SMTP.
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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.allow.telnet : Select yes to allow telnet clients to log in to the
DCM's Linux operating system, or no to disallow connections over telnet.
Select no to disable it. By default, this method is disabled for security reasons.
net.remoteaccess.allow.ssh : Select yes to allow SSH clients to log in to the
DCM's Linux operating system, or no to disallow connections over SSH. By
default, this method is enabled.
net.remoteaccess.allow.http : Select yes to allow access to the Web-based
administration system by unencrypted HTTP. (A username and password will
still be required, but they are sent over the network insecurely.) Select no to
disable it. By default, this method is disabled for security reasons.
net.remoteaccess.allow.https : Select yes to allow access to the Web-based
administration system by HTTPS (secure HTTP), or no to disable it. By default,
this method is enabled.
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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.
Alternatively, you may prefer to restrict access only to those with administrative
requirements, by removing any unprivileged user accounts. If you want to
access the DCM by any means, locally or remotely, you must have a username
and password on the list given here.
If this is the first time you have logged in to the DCM, there will be a single
user, root, whose password is factory-set. To add a new user, fill in their
username and password in the top two boxes of the page. Repeat the password
in the next box, to ensure it is entered correctly (since it will not be visible on
screen), and click on Add user. A username may not contain spaces or colons.
You should be shown an acknowledgement screen, indicating that the new user
account has been created. The user will be able to log in with that username and
password by any of the methods currently available to the device, and from any
location. More complex access controls cannot be performed through the Web
administration system, although you can of course use the features of the
DCM's underlying Linux operating system to implement them if required.
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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. To do
this, choose their username from the same drop-down box and repeat the new
password in the two boxes at the bottom of the page. Again, the password will
not be visible on screen. Click Change password to make the change.
PPP
This submenu allows you to alter the PPP configuration files,
/etc/ppp/options and /etc/ppp/chap-secrets. These two files
are required by the Linux PPP server, and affect all ppp services on the DCM.
(Separate options for each port may be specified under Serial port
configuration; see Section 4.3, “Serial port configuration”).The
/etc/ppp/chap-secrets file is only necessary if you are using CHAP to
authenticate PPP connections.
Clicking on either of these entries brings up a page in the work area which
enables you to edit the file and its attributes directly, including
• the ownership of the file;
• the permissions (read, write, or execute) of the file for its own user, its
own group, and all others; and
• the content of the file.
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, referring to the Linux manual page for pppd(8) if you are unsure.
When you have finished editing a file, clicking Save changes will write the
changes to disk. The changes will not take effect, however, until the PPP
services are restarted. You can restart all running PPP services by clicking
Restart PPP; whilst this occurs, the network will be briefly unavailable.
options
The file /etc/ppp/options sets the default options for the PPP daemon.
These will be applied to all PPP connections and to any of the serial ports which
are running the ppp service. The file is treated as a list of words, each either an
option or an argument to a previous option. For a list of the available options,
and a full explanation of the format of the /etc/ppp/options file, see the
Linux manual page for pppd(8).
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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. Each line in a secrets file contains (at least) the name of a
client, the name of the server, and a secret specific to that particular
combination of client and server.
For a full explanation of the format and usage of the /etc/ppp/chap-
secrets file, see the Linux manual page for pppd(8).
mgetty
This submenu allows you to alter the mgetty configuration files,
/etc/mgetty+sendfax/mgetty.config and
/etc/mgetty+sendfax/login.config.
Clicking on either of these entries brings up a page in the work area which
enables you to edit the file and its attributes directly.
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, referring to the Linux manual page for mgetty(8) if you are unsure.
When you have finished editing a file, clicking Save changes will write the
changes to disk. The changes will not take effect, however, until all mgetty
services are restarted. You can restart all running mgetty services by clicking
Restart mgetty; whilst this occurs, the network will be briefly unavailable.
mgetty.config
The file /etc/mgetty+sendfax/mgetty.config is the main
configuration file for mgetty.
For full details on the format of the file and the options available, see the
explanatory comments within the file, or the Linux info documentation for
mgetty.
login.config
Normal user logins are handled by the program /bin/login. However, you
may want to run a different program to handle logins by certain users. You can
do this by editing the file /etc/mgetty+sendfax/login.config.
For full details on the format of the file, see the explanatory comments within
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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. The options on this page allow you to
control how the DCM responds to requests from Scream!. Depending on your
requirements, the DCM can act either as an instrument in itself, or pass through
requests directly to connected equipment.
datatransfer.scream.server : Select on to allow Scream! to connect to the
module over a TCP/IP connection and receive data as if it were a connected
instrument. The connection can be established over an Ethernet, wireless, or
PPP link. If you do not want to transfer data directly to Scream! clients, select
off.
datatransfer.scream.server.allowserialaccess : The Scream! software allows
you to configure digitizers connected to it by serial links. Select yes if you want
to be able to use Scream! to configure digitizers attached to the DCM's serial
ports. The software is able to differentiate between several instruments
connected to the DCM, so enabling this option will allow you to configure all
attached digitizers from within Scream!.
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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. Using this option, you can prevent high-rate
streams from being transmitted to Scream!, whilst allowing them to be
transmitted by other means (e.g. CD1.1, etc.) Setting this option to zero will
filter out all data streams but preserve status channels, allowing you to use
Scream! to monitor the status of your instrumentation whilst minimizing the
bandwidth used.
Scream! Client
datatransfer.scream.client : The DCM also has the ability to act as a Scream!
client, i.e. to retrieve data from another Scream!-compatible instrument or
server on your network. This data is treated as if it came directly from an
attached digitizer, and will be collected on the hard disk or sent out across the
network according to the module's configuration. If you wish to be able to do
this, select on.
datatransfer.scream.client.port : The network port number which the DCM
should use to connect to the remote Scream! server. You can use any port which
neither device is using for other purposes. The default is 1567.
datatransfer.scream.client.server : The IP address or hostname of the Scream!
server from which you wish the DCM to gather data.
AutoDRM
AutoDRM is an automated system for handling requests for seismic data over email, and for fulfilling those requests either by returning e-mails or by
establishing an FTP connnection. In order for the AutoDRM system to work,
the module must be able to send and receive e-mail messages: this can be
configured using the Incoming and Outgoing mail setup configuration pages.
See “Incoming mail setup” in Section 4.4 for more details.
The DCM's AutoDRM capabilities are compatible with the GSE2.0 and 2.1
message standards developed for GSE-EISMS and GSETT-3.
datatransfer.autodrm : Select on to enable the DCM to handle AutoDRM
requests.
datatransfer.autodrm.maxpoolsize : The maximum pool size to use whilst
processing AutoDRM requests, in megabytes.
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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/cgi-
bin/explorefs?path=/.
You may need a username and password to access this service.
HTTP client
The DCM also has the ability to retrieve data from another instrument or server
on your network over HTTP.
datatransfer.http.client : Select on if you wish the DCM to retrieve data from
networked instruments over HTTP.
datatransfer.http.client.url : The URL from which the DCM will collect data by
HTTP.
CD1.0
Continuous Data Format, CD1.0, is a standard method for sending seismic data
over a TCP/IP network. The DCM module can send and receive data in CD1.0
format to a specific CD1.0-compatible device or NDC.
Some installations of the DCM have multiple CD1.0 senders. In this case, there
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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.compression : Select on to enable Canadian
compression in the outgoing data stream.
datatransfer.cd1.sender.channel.x : The DCM needs to know the CD1.0
channel name for each of the streams you want to transmit. When data comes in
on a stream that the DCM recognizes, it will send it on with this new name.
You can set up to 12 channels to be transmitted by one CD1.0 sender.
CD1.1
The CD1.1 format is an evolution of CD1.0 used by many NDCs, using
different settings from CD1.0. The DCM has a separate transmitter for this
format.
datatransfer.cd1_1.tx : Select on to instruct the DCM to provide data in this
format. If you do not want the DCM to transmit CD1.1 data, select off and
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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.
datatransfer.cd1_1.receiver : The IP address or hostname of the remote CD1.1
device.
CD1.1 subframe configuration
CD1.1 data is organised into subframes, which have some flexibility in their
format. A configuration file, /etc/cd11sf.cfg, is provided allowing you to
specify the exact format to be used in outgoing CD1.1 subframes. Clicking
CD1.1 subframe configuration brings up a page in the work area which enables
you to edit the file and its attributes directly.
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.
Each line in /etc/cd11sf.cfg describes a single CD1.1 stream in the
format
data-stream:status-stream:location:site:instrument:channel:prefix:
key-bucket
where the fields, separated by colons, are:
data-stream : the digitizer's data stream ID;
status-stream : the digitizer's status stream ID;
location : the CD1.1 location code for the array;
site : the CD1.1 site code for the instrument;
channel : the CD1.1 channel name;
prefix : a prefix for the location to store the files in the file tree of the DCM.
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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. and followed by a unique timestamp.
Several streams may produce files using the same prefix; indeed, this is
recommended.
Blank lines, and any lines beginning with #, are ignored.
When you have finished editing the file, clicking Save changes will write the
changes to disk. The changes will not take effect, however, until the CD1.1
service is restarted. You can restart all running CD1.1 services by clicking
Restart CD1.1.
DSS
DSS (Data Subscription Service) is a packet format which enables data and
statistics to be requested from a seismic installation. A DSS server is designed
to handle many concurrent requests from clients with varying levels of
privilege, and may prioritize requests according to their origin and urgency.
Güralp Systems' data modules include a package, libdss, which is designed
to communicate with installations using DSS as either a server or a client. A
daemon utility, dssserver, is also available which receives requests on a
network port and replies to them. This server can be loaded onto Güralp DCM
and AM data modules as required.
The dssserver program
dssserver initially listens on a network port for DSS_REG registration
packets from clients. Any incoming connnections other than DSS_REG are
refused with a DSS_REF packet. Receiving a valid DSS_REG packet, dssserver
sends a DSS_ACK packet and adds the client to an internal client list, identified
by its source IP address and port number.
Once a client is registered, dssserver will accept other DSS command
packets from it.
dssserver fulfils requests by following this procedure:
• Receiving a valid DSS_REQ packet, dssserver will send a
DSS_ACK packet immediately and add the request to an internal
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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. When a subscription
is fulfilled, it is removed from the relevant list.
• Other valid DSS commands are dealt with according to the
standard.
• When data arrives from connected digitizers, dssserver
examines the current queue of data requests, and generates the
required data or averages separately for each client, in
accordance with these requests. This data is placed in a train,
which is a data structure whose length is determined by the
reporting interval. Every train includes data from the vertical,
N/S, and E/W component of a particular instrument.
• As soon as the received or generated data fills the buffer, it is
ready for dispatch. dssserver forms the data into a DSS_DAT
message and sends it to the client, identifying it with the relevant
Data Identification Word.
• Every 10 minutes or thereabouts, dssserver checks the client list
for any clients which have not reported to it in the past 10
minutes, and purges the inactive clients from the list.
dssserver does not implement advanced prioritization or queuing schemes.
All clients connect with the same password.
Server configuration
dssserver needs to be configured before it can run. On a DCM, this can be
done by editing the text file /etc/dssserver.cfg, which determines the
mapping between incoming GCF streams and DSS stream identifiers. This file
can be edited using the DCM's Web page interface, by browsing to the
Configuration Data Transfer DSS dssserver.cfg→ → → page. Each line has
the format
stream-id:station-name:location-name:seedname
where stream-id is the Güralp stream ID, and the remaining three fields are
the stream identifiers used in DSS_REQ packets relating to that stream. A
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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.
The DCM's configuration database includes three further options relating to
dssserver, which can be altered from the Configuration Data Transfer→
DSS Server → → page.
datatransfer.dss.server : Set this to on to run the server; off to disable it.
datatransfer.dss.server.port : The port number on which to listen for incoming
DSS packets.
datatransfer.dss.server.password : The password all clients should use when
registering with dssserver.
datatransfer.dss.server.options : Any additional options to send to the DSS
server process (for advanced usage.)
Remember to click Save changes before you browse away from the page, if you
want to keep the changes you have made.
Restarting the DSS server
To force the DSS server to restart, select Configuration Data Transfer → →
DSS Restart DSS Server→ , and click the Yes button. This action will
immediately kill any running DSS servers, and currently-activated subscriptions
will be terminated without notice. Clients will have to register with the new
instance of dssserver before they can continue receiving data.
SEED
The DCM can compile full SEED volumes in real time. To enable this, select
yes for the disk.recordas.seed option under Configuration Disk→ (see above.)
A configuration file, /etc/seed.cfg, is provided allowing you to provide
technical information about the streams to be recorded in SEED format. The
DCM will only write SEED volumes for streams mentioned in this file.
Clicking SEED configuration brings up a page in the work area which enables
you to edit the file and its attributes directly.
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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:V1.050E00:1.6E-07:46
Each line represents an incoming stream from the digitizer; the fields are
separated by colons, and are in turn:
• the digitizer's stream ID;
• a SEED network name for the array (or leave blank to have the DCM
generate one automatically);
• a SEED station name for the station (or leave blank to have the DCM
generate one automatically);
• a SEED location name for the instrument (or leave blank to have the
DCM generate one automatically);
• a SEED channel name for the stream (or leave blank to have the DCM
generate one automatically);
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• 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. The sensitivity
of a sensor integrated with a digitizer is quoted as a single-ended
sensitivity, whilst stand-alone digitizers are provided with their
differential sensitivity. A differential sensitivity is quoted as, e.g. 2 ×
3000 V/m/s. In this file, you should use the doubled value, i.e. 6000
V/m/s, for a stand-alone digitizer. For integrated digitizers, you should
use the single-ended value quoted.
• the sensitivity of the digitizer, in volts per count (here 1.6 × 10
-7
V/count
= 0.16 V/count). This is given on the digitizer's calibration sheet.μ
• the decimation sequence code. This is an integer between 0 and 239
which describes the sequence of filters in use by the digitizer. If you
have a recent digitizer (with firmware newer than version 0.91) this
information is included in the incoming GCF streams, so you can leave
this field blank. The codes corresponding to each possible decimation
sequence are available from the support section of the Güralp Systems
Web-site.
When you have finished editing the file, clicking Save changes will write the
changes to disk. The changes will not take effect, however, until the SEED
service is restarted. You can restart the SEED volume generator by clicking
Restart SEED recorder.
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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.
The main part of the display shows a selection of the data streams being
recorded, whilst the bars at the top and bottom allow you to control what is
displayed, and in what manner:
If you cannot see any data in the Data Viewer, you should check first that
• some streams have been checked in the lower portion of the applet, and
• the data has been offset correctly. You can automatically zero the
streams by clicking on the icon depicting a “0” and a sine wave in the
icon bar. Otherwise, you can zoom out until the streams are visible.
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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. There are:
• four icons allowing you to alter the X and Y scaling factors of the graph
(from left to right: magnify X, reduce X, magnify Y, and reduce Y)
• a bandpass filter toggle (not currently available),
• a toggle to display the endpoints of each GCF block as a white line,
• a pause button, which will cause the viewer to stop scrolling as it
receives new data, and
• a zeroing button, which attempts to centre all the selected streams in the
display.
The stream list
Below the display is a list of all the streams currently being recorded by the
DCM. Each has a checkbox indicating whether that stream is currently being
displayed.
To the right of the checkboxes, you are given information about each stream,
similar to that found in the main window of Scream!. The information provided
is:
• The ID of the stream (six characters long);
• The compression code corresponding to the bit depth of the data. 0 = 8-
bit data, 1 = 16-bit data, 2 = 24-bit data, and 3 = 32-bit data;
• A recent FIC for the data. The FIC gives a rough idea of the magnitude
of the signal being received.
• Finally, the time the most recent data block was received, including, in
brackets, the day number within the year (1 = January 1, etc.)
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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. This will
take a few seconds, after which the message Configuration
successfully retrieved from attached instrument should
appear together with a form detailing the available settings.
If the DCM cannot find a digitizer attached to the port, it will give the message
Unable to retrieve configuration from attached
instrument. In this case you should
• check that an instrument is connected to the port you clicked, and that it
is powered up;
• check that the baud rate of the serial port (see Section 4.3, “Serial port
configuration”) matches the output baud rate of the digitizer; and
• check that the DCM is running the gcf_in service on the port (see
Section 4.3, “Serial port configuration”.)
Assuming that the DCM has detected an instrument, its current configuration is
now shown on the right side of the page for reference. In the centre of the page,
the settings are repeated in a form that you can change. Once you have finished
making changes, click Configure instrument. The DCM will then attempt to
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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. This must match the baud rate the DCM is using for the
serial port linked to this digitizer. The DCM's baud rates can be altered on the
various Serial port configuration pages: see Section 4.3, “Serial port
configuration”.
You should ensure that the baud rate is high enough to allow all the data to be
transmitted at the rates you have chosen. As an example, for three streams
transmitting at 100 Hz, a rate of 9600 baud is usually sufficient. Modern
modems can normally operate at rates up to 57600 baud (~56 kbits/s), although
the telephone or transmission lines may not support such a high rate. The same
is true of radio telemetry links.
System ID and serial number : Together, these two fields uniquely identify data
originating from a particular instrument. Every data or status block sent by the
digitizer will contain them as the first two 32-bit fields in the header, each
encoded as a sequence of 6 base-36 numbers representing alphanumeric
characters. On delivery of the digitizer from the factory, the system ID is set to
the Güralp Systems works number, and the serial number is unique for that
digitizer (unless shared with an attached seismometer). You may reset these
values to any combination of up to 6 letters and numbers. For example, you may
wish to set the system ID to a more easily-recognised value, such as an
abbreviation of your institution's name.
Sensor type : If the sensor attached to the digitizer is a Güralp velocity sensor,
useful seismometer functions (such as sensor locking, centering, and
calibration) may be controlled through the digitizer and DCM. In order to be
able to do this, and to know which functions to make available, the digitizer
must be set up with the correct sensor type: one of CMG-40T, CMG-3ESP, or
CMG-3T. The sensor's type will be printed on its casing. If you have taken
delivery of a DCM already bonded to a sensor and digitizer, this field will have
been set for you at the factory, and should not be altered.
Timing source : The digitizer needs to be able to time-stamp accurately all data
that passes through it. It can set its clock either by receiving time signals from
the GPS satellite network using an attached Garmin GPS unit, or by taking time
information from a central site via the DCM (stream sync mode). In stream
sync mode, the digitizer expects to receive GCF packets from the central timing
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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. Between timing fixes the
instrument will run on its internal clock, saving power at a small expense in
accuracy. If your instrument has ready access to a power source, you should
select always on.
Digitizer output control
The analogue-to-digital converters on a Güralp digitizer output data sampled at
2000 Hz, which is then filtered and reduced to a lower rate (decimated) using an
on-board digital signal processing (DSP) unit. The DSP has four filteringdecimation stages, which run one after the other. Each can be programmed to
reduce the sampling rate by a factor between 1 and 10. The output of each stage
is called a tap. Each of the taps may be configured for a different decimation
factor by choosing values from the drop-down menus on the left. If you are
using a mouse wheel to select values from a drop-down menu, ensure you
remove the focus from the drop-down menu before scrolling the window, or
you may inadvertently change the setting.
Note that not all digitizers support the full range of taps and decimation factors.
For example, the Güralp DM24 allows you to select decimation factors of 2, 4,
5, 8, and 10 only, and does not allow the decimation factor of Tap 0 to be
altered from its default setting of 10. In addition, no combination of decimation
factors may be used which produces a non-integer data rate (in Hz). A full list
of possible tap combinations for the DM24 is given in “Trigger criteria” in
Section 5.2, below.
To the right of each decimation factor menu is a grid of six check-boxes marked
Z, N, and E. These boxes mark which streams of data to record at each sample
rate. Three streams of data are measured by the seismometer, corresponding to
movement along each of three perpendicular axes. Although all the streams are
decimated by the same set of successive scale factors, you can decide at which
stage(s) of processing each stream outputs data. A tick in one of the check
boxes will produce an output for a particular channel (column) at the
corresponding sample rate (grid).
Each grid also has two rows, which differentiate between constant and triggered
output. If a box in the upper row is ticked, that stream will produce output
constantly at the corresponding sample rate. If the box below it is ticked, that
stream will only produce output at that rate if a particular set of trigger criteria
are also met. If the constant-output check box is ticked, the other will be
ignored.
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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.
Additionally, when the trigger criteria are met,
• the N data stream will be output by Taps 0, 2 and 3 at rates of 2000/10 =
200 Hz, 2000/10/4/2 = 25 Hz and 2000/10/4/2/5 = 5 Hz, and
• the E data stream will be output by Taps 1 and 3 at rates of 2000/10/4 =
50 Hz and 2000/10/4/2/5 = 5 Hz.
The next section allows you to alter the criteria that the digitizer uses when
deciding whether a trigger event has occurred.
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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.
You can select which tap is tested for the trigger from the Trigger source dropdown menu. The tap does not have to be selected for data output for you to be
able to use it here.
The next option, Trigger filter, allows you to apply a bandpass filter at this
stage (see below.)
Any or all of the channels available at the tap you have selected may be used to
determine a trigger. The next part of the window lists the channels, each with
Enable, STA, LTA and Ratio settings. The Enable boxes determine which
channels are considered for triggering. If any of the checked channels passes the
trigger condition, the trigger will activate, and will not detrigger until all of the
checked channels have fallen below their respective Ratio values.
The STA and LTA columns allow you to set the intervals over which the two
averages are calculated, in seconds. Typically, the time interval for the short
term average should be about as long as the signals you want to trigger on,
while the long term average should be taken over a much longer interval. Both
the STA and LTA values are recalculated continually, even during a trigger.
The Ratio column determines by what factor the STA and LTA must differ for
the trigger to be passed. Finding the ratio most suited to your needs is best done
by experiment. Too high a value will result in events being missed, while too
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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.
For example, setting the STA to 1 second, the LTA to 10 seconds and the Ratio
to 4 would give rise to the following trigger behaviour:
Usually, the values of the STA and LTA periods, and of the Ratio, will be the
same for all checked channels. For convenience, Scream! will automatically fill
in other values to match ones you enter. If you want to use different values for
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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. This filtering serves to maximise
sensitivity within a the frequency band of interest, and filter out noise outside
this band. You can select which bandpass filter to use from the Trigger filter
drop-down menu. The corner frequencies of the pass band of the filter are
determined by the Nyquist frequency, which is given by the sampling rate of the
triggering data. The three filter options have pass bands between 10 % and 90
%, between 20 % and 90 % and between 50% and 90% of the data’s Nyquist
frequency, respectively.
The possible filter configurations are shown in the following table:
Tap #
Rate
(samples/s)
Bandwidth 1
(Hz)
Bandwidth 2
(Hz)
Bandwidth 5
(Hz)
0 200 10 – 90 20 – 90 50 – 90
1 100 5 – 45 10 – 45 25 – 45
50 2.5 – 22.5 5 – 22.5 12.5 – 22.5
40 2 – 18 4 – 18 10 – 18
25 1.25 – 11.25 2.5 – 11.25 6.25 – 11.25
20 1 – 9 2 – 9 5 – 9
2 50 2.5 – 22.5 5 – 22.5 12.5 – 22.5
25 1.25 – 11.25 2.5 – 11.25 6.25 – 11.25
20 1 – 9 2 – 9 5 – 9
10 0.5 – 4.5 1 – 4.5 2.5 – 4.5
8 0.4 – 3.6 0.8 – 3.6 2 – 3.6
5 0.25 – 2.25 0.5 – 2.25 1.25 – 2.25
4 0.2 – 1.8 0.4 – 1.8 1 – 1.8
2 0.1 – 0.9 0.2 – 0.9 0.5 – 0.9
3 25 1.25 – 11.25 12.5 – 11.25 6.25 – 11.25
10 0.5 – 4.5 1 – 4.5 2.5 – 4.5
5 0.25 – 2.25 0.5 – 2.25 1.25 – 2.25
4 0.2 – 1.8 0.4 – 1.8 1 – 1.8
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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.
Auxiliary (“Mux”) channels
Güralp digitizers provide a range of slow-rate auxiliary channels for reporting
the system's state of health and other diagnostic information, known as
multiplexed (“Mux”) channels. The number of Mux channels depends on the
model and configuration of your digitizer. Generally, three channels are used to
report the sensor mass position, and another measures the internal temperature
of the digitizer. In addition to these, up to 12 Mux channels may be supplied for
the user's own purposes. Some digitizers have a separate AUXILIARY port
which can be used to access these channels.
You can choose which, if any, of these channels should be transmitted to the
DCM in the next section of the page. If one of the check-boxes is ticked, the
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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.
For more information on the format of data packets transmitted on the Mux
channels, please refer to the documentation supplied with your digitizer.
Sensor mass control
There are three commands which can be relayed to an instrument through the
DCM to control the position of its sensor mass. For each instrument the buttons
which perform these commands (Centre instrument, Lock instrument, and
Unlock instrument) can be found at the bottom of the relevant Digitizer Setup
page. The type of sensor you have installed determines which, if any, of these
commands have any effect.
• The CMG-40T sensor type has no mass lock or centring capabilities, so
all three buttons are inactive.
• The CMG-3ESP sensor type has manual mass lock and remote centring,
so only the Centre instrument button is active.
• The CMG-3T sensor type is an automated analogue instrument, with all
three commands available.
• The CMG-3TD sensor type is a fully digital borehole instrument, with
all three commands available.
Lock and Unlock instrument are provided so that you can secure the
seismometer's sensor mass for safe transportation. Once installed and unlocked,
you should Centre instrument to move the mass to the correct position to start
measuring data. During the execution of any of these commands, the system
will display the three components of the mass's current position and update
them once per second per component. When the masses are locked, the position
readings will be in the region of 32,000 or 32,000 counts. When the masses−
are correctly centered all three readings should be less than ±1,000 counts.
Locking or unlocking the sensor mass typically takes several minutes to
complete.
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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.
Partition, and format disk
Before using the CMG-DCM you should ensure that its primary hard disk is
ready to receive data by partitioning and formatting it. The DCM uses a special
journalling format for the hard disk which is designed to maintain the integrity
of your data at all times. The hard disk is guaranteed to contain a FAT32compatible filesystem, even if a write operation fails or is aborted suddenly.
Check disk filesystem
Clicking on this button will verify the integrity of the hard disk's filesystem. It is
recommended that you do this immediately after installing the device.
Flush flash
Clicking on this button will cause the DCM to dump the current contents of its
Flash memory to the hard disk, thus synchronizing it with the most current data.
If you want to remove or replace the DCM's hard disk, using this tool will
ensure that the outgoing disk is up-to-date. Flush flash does not remove data
from the DCM's on-board Flash memory. If you Flush flash and then swap hard
disks, the data remaining in memory will later be written out to the new hard
disk, causing some overlap between it and the old disk.
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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.
If no suitable storage medium can be found, the module will report the error
Failed to open USB disk.
5.5 Camera
If you have attached a compatible camera to the external USB port of the DCM,
clicking on this link will show the current view from the installation site. A new
image is retrieved every 12 seconds, or whenever you reload the page. Güralp
Systems can supply a compatible camera with the DCM, although any
STV0680-based device can be used.
5.6 Recent Log Entries
This link displays the most recent 300 entries written to the DCM's internal log
file.
Each entry includes, in order:
• the date and time of the log message,
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• 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. It is divided into a number of sections:
Network configuration
This section displays basic information about the DCM's network setup. It is
identical to the output from the Linux ifconfig program. A typical reading
might look like this:
eth0 Link encap:Ethernet HWaddr 00:D0:1F:34:EB:08
inet addr:192.168.0.46 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:3619 errors:0 dropped:0 overruns:0 frame:0
TX packets:2453 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
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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.conf.
Data Out Port, Serial Port A, Serial Port B
The next three sections report information about the DCM's serial interfaces. A
typical reading for one port might be:
/dev/ttySA0, 115200 baud, none handshaking, service getty
0 GCF blocks received on this port
In this example, /dev/ttySA0 represents the device name of this serial port
in the Linux filesystem. The remaining information on this line reflects the
current setup of the port, based on your choices on the Serial port configuration
page. See Section 4.3, “Serial port configuration” for more details.
115200 baud : The speed of data exchange over this link, as set up by the
serial.x.baudrate option.
none handshaking : The flow-control protocol used over this link, as set
up by the serial.x.handshaking option.
service getty : The service provided over this link, as set up by the
serial.x.service option.
The second line reports how many valid blocks of GCF (Güralp Compressed
Format) data have been received over this link since the last reset or change in
data port configuration. If the link is being used for a service other than GCF
data transfer, this number may be disregarded.
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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).
Tamper lines
This section, if present, reports the status of the tamper lines relayed to the
DCM over an external State of Health interface:
Input State Last Closed (Low) Last Open (High)
0 open (never) Wed Jul 7 16:04:48 2004
1 open (never) Wed Jul 7 16:04:48 2004
2 open (never) Wed Jul 7 16:04:48 2004
3 open (never) Wed Jul 7 16:04:48 2004
4 open (never) Wed Jul 7 16:04:48 2004
5 closed Wed Jul 7 16:04:48 2004 (never)
6 open (never) Wed Jul 7 16:04:48 2004
7 closed Wed Jul 7 16:04:48 2004 (never)
8 closed Wed Jul 7 16:04:48 2004 (never)
9 closed (never) (never)
10 closed (never) (never)
11 closed (never) (never)
12 closed (never) (never)
13 closed (never) (never)
14 closed (never) (never)
15 closed (never) (never)
The columns in the table give, in turn, the current state of each switch and when
it was last observed to be in each state. The above example shows a typical
reading for a set of 9 tamper switches that have not triggered: the normallyclosed switches show the current time under “Last Closed”, and the normallyopen switches under “Last Open”. All other fields show (never), indicating
that no switches have been observed in the “wrong” state since the DCM was
last booted.
Disk Status
This section reports the current state of the DCM's primary hard disk. The
module looks on its USB interfaces for an on-board 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.
Assuming that the DCM successfully found a primary hard disk, you will see
information in a format like this:
FAT32 filesystem has 15 G bytes free
Partition is 37 G bytes (78140097 blocks of 512 bytes)
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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.
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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. This
can be any of
• a digitizer connected through a serial link,
• a computer running a Scream! server,
• a CD1.0 or CD1.1 transmitter (optionally), or
• another DCM or AM.
All the received data is stored in files in the on-board Flash memory. There are
two banks of Flash memory available, which are accessible as /nand0 and
/nand1 in the Linux file tree. Data is normally stored as GCF (Güralp
Compressed Format) files.
As an option, you may be able to configure the DCM to use the miniSEED or
sac formats instead (see Section 4.2, “Disk”)
In automatic mode, when the Flash memory becomes more than 75% full, the
oldest data files are moved to the DCM's primary hard disk until it is less than
50% full. If you prefer, you can configure the DCM to write to the hard disk at
set intervals (see Section 4.2, “Disk”.)
Writing to the hard disk is performed robustly, so that no data will be lost if a
write is aborted (see Section 6.1, “File systems”.) This means that you can
safely swap hardware in and out at any time. Stand-alone DCM modules use
off-the-shelf Lacie hard disks, which can be easily removed and installed in
most conditions. You can specify other models of IDE / USB or IEEE 1394 2.5”
disk at manufacture. If an internal disk is not present, and the module has a USB
host interface, it will look for hard disks connected to its external USB port.
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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 GCF-
compatible 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.
A PC running Güralp Systems' Scream! software can not only collect data from
the DCM, but also configure the module and any instruments attached to it.
You may need to enable and configure some of these methods before you can
use them: see Chapter 4, “Configuration options” for more details.
Most installations of the DCM will not require any more complex setting up
than the Web configuration system can offer. However, in some cases you may
need to take advantage of the flexibility offered by the underlying Linux
operating system.
6.1 File systems
The DCM uses the standard Unix/Linux file naming conventions. The operating
system resides in two blocks of Flash memory, mounted on / and /boot;
when the module is powered up, a separate boot loader loads the rest of the
operating system.
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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 4.2, “Disk”), then
each file will be named after the timestamp on its first packet of data, in the
following fashion:
file-yyyymmdd-jjj-s-cccccccc.gcf where yyyymmdd represents
the date of the earliest data packet in the file, jjj the number of full days
elapsed since midnight on January 1, s the time segment within the day (each
day is divided into eight 3-hour segments), and cccccccc a unique
hexadecimal code included to ensure filenames do not coincide.
When one of the Flash memory blocks approaches capacity, or after a fixed
time period (if you have so configured it; see Section 4.2, “Disk”) the DCM will
automatically move them onto the primary USB hard disk. This may be either
an internal Lacie hard disk, or an external drive connected to the module
through a USB client interface. This disk uses a specially-designed journalled
filesystem, which is designed to maintain the integrity of your data at all times.
Even if a write operation fails or is aborted suddenly, the disk will still contain a
valid filesystem with all previously-saved data intact, which can be read using
any driver that supports FAT32.
There is a set of specialised commands which allow you to perform basic tasks
on this filesystem:
gfat32df : Displays the size of the filesystem, and how much free space
remains, in a format similar to this:
FAT32 filesystem has 15 G bytes free
Partition is 37 G bytes (78140097 blocks of 512 bytes)
If no suitable storage medium can be found, you will see the message Failed
to find a USB disk.
diskman : Ensures that the /nandx partitions do not become full by moving
files when necessary. This program ordinarily runs constantly in the
background. However, a user can use the command diskman -f to force the
Flash memory to be entirely copied to the USB disk. Typing diskman -f is
identical to clicking the Flush flash button on the Disk tools page (see “Flush
flash” in Section 5.3). It does not remove data from the Flash memory. If you
issue diskman -f and then swap hard disks, the data remaining in memory
will later be written out to the new hard disk, causing some overlap between it
and the old disk.
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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. The automatic options are chosen to minimize this likelihood by
only moving the oldest files, and by keeping files in Flash memory for a
reasonable period of time. If you choose to transfer files to disk more often than
this, more files will be fragmented.
gfat32 ls : List the files present on the hard disk, with the size of each file.
gfat32 cpf filename-on-disk destination-filename : Copy
a file from the disk into temporary storage in the Linux filesystem (e.g. in your
home directory.) Once the file is in the Linux file system, you can modify or
convert it using your own scripts running on the DCM, or use programs such as
scp to transfer it to a remote machine.
gfat32 cpt source-filename filename-on-disk : Copy a file
from the Linux file system onto the disk.
gfat32 mv filename new-filename : Rename a file on the disk.
6.2 Command line tools
The DCM module's Linux operating system can be accessed over a network via
SSH. There are many programs available for your computer which implement
this protocol: ssh is included as part of most Linux and Unix distributions,
whilst for Windows putty is a reliable free client. ssh is essentially a secure
version of programs like rlogin and telnet, and provides a simple
command line interface to the device. Access to the DCM by SSH is enabled by
default, although you can disable it using the net.remoteaccess.ssh configuration
option (see “Remote access” in Section 4.4).
In addition, if you have so configured it, you can connect directly to an RS232
port running the getty service.
Once the connection has been set up and you have logged in, you will then be
shown a command prompt:
~ #
By default, your account uses the standard Bourne shell, sh. If you prefer, the
more advanced shells ash and bash are also available. Many standard Unix
programs are also present: ls, cat, more, sed, etc.
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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.
6.3 Configuration
Configuring the DCM is automated by a suite of command line tools. These
maintain a configuration database and check that all the relevant Linux files are
kept up to date. If you alter the standard Linux configuration files, you should
bear in mind that these tools will overwrite them without checking that they
match the information in the database. Because of this you should use the tools
wherever possible rather than editing the files directly. The DCM's Web-based
configuration system is just a front-end to these tools.
gcfgdbls prefix : Enter this command to find out which configuration
options begin with the prefix prefix (case sensitive—all the configuration
options are in lower case). The options are listed in alphabetical order. For
example:
~ # gcfgdbls serial.0
serial.0.baudrate
serial.0.handshaking
serial.0.ppp
serial.0.service
gcfgdbset option-name new-value : Enter this command to set the
value of the named option to new-value. The database will perform a simple
type check on your value (for example, to check that certain options are
numbers), but will not otherwise make sure that your change makes sense.
gcfgdbget option-name-or-prefix : Enter this command to find the
current value of the named option. Instead of a single option name, you can also
use a prefix (as described above) to find out the values of a range of options.
The remaining tools also allow you to use prefixes in place of full option
names.
Each option in the database can be marked either as “clean” or as “dirty”. This
flag tells the DCM whether the database is currently in sync with the state of the
device. Whenever you alter the value of an option using the gcfgdbset tool,
or using the Web interface, the option is marked as “dirty”; the DCM then alters
its configuration, and marks the option as “clean” again, to signify that the
change completed successfully. Three more commands are provided to allow
you to access this flag:
gcfgdbmark clean option-name-or-prefix : Enter this command
to mark the named configuration option as “clean” in the database.
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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-or-
prefixes ... ) : 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. Thus you can use gcfgdbisdirty in
your own shell scripts, to perform actions depending on the status of the DCM's
configuration options.
Note that marking an option as “dirty” will not necessarily lead to any action
being taken. For example, you cannot force a service to be restarted using these
commands.
Each of the four tools can also take two command-line options:
gcfgdbxxx -h : Displays a short usage reminder about the command
gcfgdbxxx. All other arguments will be ignored.
gcfgdbxxx -c config-database other-arguments : Normally,
all the gcfgdbxxx commands work on the system configuration database.
However, you can supply the file name of an alternative database using the -c
option, in which case the command will be performed on that database instead.
For a detailed description of the configuration options in the database, see
Chapter 4, “Configuration options”.
Digitizer console access
The command gcli allows you to pass commands directly to the digitizer's
console. The syntax is:
gcli port-number [-f] [-r] command
where port-number refers to the serial port connected to the digitizer. You
can use serialmap to discover which serial port has which number, as
described below. command is a DM24 FORTH command, which may contain
several words. For information on the commands available on the DM24, please
see its own documentation.
gcli will wait for the digitizer command to finish before exiting, and will only
output any response from the digitizer afterwards. If you need to issue a
command which monitors a value, you will need to connect to the digitizer's
console directly using Scream! or minicom.
If you want to pass special characters to gcli, using the -f option allows you
to use backslash sequences as used by the C command printf (e.g. \t = tab
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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.
If you need an interactive session with the digitizer, you can use the Linux
terminal program minicom, which has been configured specially to cooperate
with the DCM's various serial services. You can open a session with a digitizer
by issuing the command
minicom -n port-number
If the port you specify is set to gcf_in, the DCM will automatically interrupt the
data flow from the digitizer to allow you to enter commands.
When you have finished your session, press CTRL-a then q. minicom will
ask you if you want to quit without resetting the connection. Choose yes to
return the digitizer to data mode.
6.4 Monitoring
Data flow
You can check that the DCM is receiving data either by monitoring the
Summary page of the on-board Web interface (see Section 5.7, “Summary”), or
from a command prompt using the command gnblocks:
Key 0x007000: Blocks 0 (Port 0, name Data out port,
device /dev/ttySA0, baud 115200)
Key 0x007001: Blocks 0 (Port 1, name Port B, device
/dev/ttySA1, baud 9600)
Key 0x007002: Blocks 149 (Port 2, name Port A, device
/dev/ttySA2, baud 38400)
This command shows, for each port:
• the Key number (in hexadecimal) of the process on that port which deals
with incoming blocks,
• the number of blocks received by that process,
• the internal port number of the port,
• the name you have assigned to it,
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• 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. A line will be output for each
serial port, in the form
Port 0, Key 7000, name tts0, device /dev/ttyS0, baud 115200
where port and baud are in decimal, and Key in hexadecimal. The related
command serialmap -k returns the key ID in decimal.
Digitizer status
The Güralp DM24mk3 digitizer outputs status information as a separate stream.
If you have a DM24mk3, you can monitor this stream with the command
dm24mk3cds -s port-number
Whilst this program is running, it will output any status blocks it receives on
that port directly onto your terminal:
HPA1CD: Wed Jun 30 14:51:13 2004
gps_fix=2 (0x32)
gps_mode=A (0x41)
gps_control=255 (on)
gps_power=255 (on)
gps_offset=167 ticks
busy_counter=0 ticks
locking=0 unlocking=0 centering=0
calibration V N E
The information given, after the stream ID (which will always end in CD), is as
follows:
• a time-stamp for the status block;
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• 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 counts down towards zero
whilst certain digitizer processes (such as calibration) are active;
• whether the sensor is currentlty being locked, unlocked, or centred;
• which, if any, of the channels are currently being calibrated (the channel
appears with a + if this is the case).
Tamper lines
The command tamper provides information about the current state of the
DCM tamper lines. Issued with no arguments, it will output the status of all
tamper lines once every 10 seconds. Including the -w option causes it to exit
after printing the status once only:
[root@dcm-87AD9C933DE1 ~]# tamper -w
Input State Last Closed (Low) Last Open (High)
0 open (never) Mon Jan 5 21:50:37 1970
1 open (never) Mon Jan 5 21:50:37 1970
2 open (never) Mon Jan 5 21:50:37 1970
3 open (never) Mon Jan 5 21:50:37 1970
4 open (never) Mon Jan 5 21:50:37 1970
5 open (never) Mon Jan 5 21:50:37 1970
6 open (never) Mon Jan 5 21:50:37 1970
7 open (never) Mon Jan 5 21:50:37 1970
8 closed (never) (never)
9 closed (never) (never)
10 closed (never) (never)
11 closed (never) (never)
12 closed (never) (never)
13 closed (never) (never)
14 closed (never) (never)
15 closed (never) (never)
The output of the tamper command is included on the Summary page under
Actions on the DCM Web site.
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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.
Running upgrade will restore the DCM to its factory settings, so make
sure you will still be able to communicate with it before you issue the
command, either
• over a serial link to the DATA OUT port (115200 baud, 8 data bits, no
parity bit, 1 stop bit, no flow control), or
• over a DHCP-enabled network (using an IP address provided by the
DHCP server.)
From the hard disk
If your DCM does not have access to the Internet, you can update its software
from a connected USB disk. You will need to make a copy of all the files in the
directory http://www.guralp.net/cmgdcm/feeds, including all subdirectories, in a
directory called /cmgdcm/feeds on the hard disk. On Linux, you can do this
with the command
wget -np -nH -m http://www.guralp.net/cmgdcm/feeds
Once the files are on the hard disk, you can install it in a DCM and transfer the
packages with the command
upgrade gfat32
This facility is available with versions 2.10 and greater of the upgrade
package.
Removing support packages
The DCM as shipped includes a package gsl-backdoor which enables
Güralp Systems to respond to support issues by remote administration (e.g.
installing updated firmware or packages.) If you prefer not to allow Güralp
Systems access to the DCM you should use the command
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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. We recommend that you use only upgrade wherever
possible, to ensure that you have a fully tested set of packages.
The firmware
Reinstalling the firmware from scratch is a more involved process, and you
should only need to do it if the root or boot partitions of the DCM become
corrupted. In this case, you can use the boot loader (which is resident in
hardware) to update them. You will need a second DCM or Linux computer
attached to the console port in order to do this.
Note that the firmware is not the same as the distribution. If you want to ensure
that your DCM has all the latest software, you should use the upgrade
command described above. Reinstalling the firmware will reset any changes you
have made to the system.
The procedure for installing new firmware depends on which revision of the
DCM design you have. All recent DCM units use “MkII” firmware. If you are
unsure which hardware type you are using, contact Güralp Systems.
MkII DCM or AM
Mark II DCMs and AMs have a 256 kb bootloader, a 1 Mb kernel image and a
64 Mb file system image. Currently all surface DCM units are the Mark II
design.
1. Download the latest revision of the root (and boot, if appropriate) files
from the Güralp Systems website at
http://www.guralp.net/software/modules/DCM/
2. Obtain the flashdcm tool from the same site. This is a Linux utility
which enables you to access the DCM's firmware. If you are using a
second DCM, flashdcm will already be present on it.
3. Note the baud rate of the DCM's console port (115200 by default).
4. Power down the DCM.
5. On the second computer or DCM, issue the command
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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.
If the device has several serial interfaces, the command serialmap
may help you determine which port number corresponds to which
device:
[root @ dcm] # serialmap
Library version: libserialmap Version 1.0.5 with
LIBGCONFIGDB
4 serial ports
Port 0, Key 7000, name ttyS0, device /dev/ttyS0, baud
38400
Port 1, Key 7001, name ttyS1, device /dev/ttyS1, baud
19200
Port 2, Key 7002, name ttyS2, device /dev/ttyS2, baud
19200
Port 3, Key 7003, name ttyS3, device /dev/ttyS3, baud
19200
flashdcm also has an -e option, which wipes clean the Flash memory
used for the filesystem before providing the new firmware. Some surface
DCM units require you to do this when installing a root image. If you
use the -e option to install a root image, you must also provide a new
boot image, since the boot image in memory will be erased.
6. Power up the DCM. The second computer or DCM will detect messages
coming from the bootloader of the DCM, and automatically interrupt the
boot process to provide the new firmware.
7. Wait for the new firmware to be uploaded. The DCM will reboot
automatically at the end of transmission, and the flashdcm process
will terminate. This may take several minutes.
At this point, you will have a minimal installation of the DCM software, and
can proceed to commissioning the system.
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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). The pinout is the same as
the serial output of a DM24 digitizer, allowing you to insert a DCM into a preexisting installation and maintain connectivity.
Pin Function
A Power 0 V
B Power +10 to +35 V
C RS232 CTS
D RS232 RTS
E RS232 DTR
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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).
Pin Function
B Data transmit +ve (RJ45 pin 1)
C Data receive +ve (RJ45 pin 3)
E Data receive –ve (RJ45 pin 6)
F Data transmit –ve (RJ45 pin 2)
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Appendix A.2 Integrated DCM units
DM/AM module output
This is a standard 32-pin mil-spec plug (02E-18-32P).
Pin Function
D Power +10 to +30 V
E Power 0 V
J Data transmit +ve
K Data transmit –ve
L Data receive +ve
M Data receive –ve
R AM console receive
S AM console transmit
T AM console ground
U Tamper switch 5
V GPS 1pps signal
W GPS RS232 transmit
X GPS RS232 receive
Y GPS RS232 ground
Z DM console transmit
a DM console receive
b DM console ground
c Tamper switch 0
d Tamper switch 1
e Data ground
f Tamper switch ground
g Tamper switch 2
h Tamper switch 3
j Tamper switch 4
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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.1 Sensor response codes
Sensor Sensor type code Units (V/A)
CMG-5T or 5TD, DC – 100 Hz response
CMG-5_100HZ A
CMG-40T-1 or 6T-1, 1 s – 100 Hz response
CMG-40_1HZ_50HZ V
CMG-40_1S_100HZ V
CMG-40T-1 or 6T-1, 2 s – 100 Hz response
CMG-40_2S_100HZ V
CMG-40T-1 or 6T-1, 10 s – 100 Hz response
CMG40_10S_100HZ
V
CMG-40, 20 s – 50 Hz response
CMG-40_20S_50HZ V
CMG-40, 30 s – 50 Hz response
CMG-40_30S_50HZ V
CMG-3T or 3ESP, 30 s – 50 Hz response
CMG-3_30S_50HZ V
CMG-40, 60 s – 50 Hz response
CMG-40_60S_50HZ V
CMG-3T or 3ESP, 60 s – 50 Hz response
CMG-3_60S_50HZ V
CMG-3T or 3ESP, 100 s – 50 Hz response
CMG-3_100S_50HZ V
CMG-3T or 3ESP, 120 s – 50 Hz response
CMG-3_120S_50HZ V
CMG-3T, 360 s – 50 Hz response
CMG-3_360S_50HZ V
CMG-3TB or 3V / 3ESP borehole, 30 s – 50 Hz
response
CMG-3B_30S_50HZ V
CMG-3TB or 3V / 3ESP borehole, 100 s – 50 Hz
response
CMG3B_100S_50HZ
V
CMG-3TB or 3V / 3ESP borehole, 120 s – 50 Hz
response
CMG3B_120S_50HZ
V
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Appendix B.2 Digitizer type codes
Digitizer Digitizer type code
CMG-DM24 mk2 (3- or 6- channel)
CMG-DM24
CMG-3TD or 5TD using DM24 mk2 module
CMG-DM24
CMG-DM24S12 (including AMS)
CMG-DM24
CMG-DM24 mk3
CMG-DM24mk3
CMG-6TD
CMG-6TD
98 Issue A
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