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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
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CMG-DCM Table of Contents 1 Introduction............................................................................................................................5 1.1 Inside the DCM................................................................................................................7 Serial port services.............................................................................................................8 Network services.......................................................
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Operator's guide 4 Configuration options..........................................................................................................40 4.1 General...........................................................................................................................40 4.2 Disk................................................................................................................................41 4.3 Serial port configuration..............................................
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CMG-DCM Tamper lines....................................................................................................................80 Disk Status ......................................................................................................................80 Software Versions............................................................................................................81 6 Inside the DCM....................................................................................
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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
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CMG-DCM Retrieving data from a DCM's disk can be done by plugging it into a computer compatible with the USB or FireWire mass storage standards. Disks can be swapped at any time with no risk to data. • A stand-alone DCM can also be supplied in a form factor suitable for mounting in a standard 19” rack. Such a DCM will normally come equipped with eight additional serial ports TTS0-7, and an optional State of Health (SOH) interface for monitoring or tamper evidencing. Up to four module
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Operator's guide This form of DCM uses an integrated 26-pin connector to communicate, rather than having separate ports. A DCM in any of these forms may be supplied in the configuration most suitable to your requirements, depending on how you wish it to be connected to your network, and how its USB interface is to be used. The two sets of options are independent. • Using the 10BaseT Ethernet network option, you can connect the DCM to any TCP/IP network. • Alternatively, an internal PCMCIA m
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CMG-DCM The two main areas which need to be configured determine the different services which the DCM provides from its serial and network ports. Serial port services You can use either the DCM's console or its Web configuration interface to configure the serial data ports. The serial.x.service configuration option determines which service each port provides. • The simplest service is getty. This creates a console port, which you can use to log in to the Linux operating system of the DCM di
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Operator's guide do not have a DHCP server, you will have to set the IP address yourself. 2. Find out the IP address the DCM is using (if you have not set it yourself). 3. If necessary, configure your own computer's IP address so that it can communicate with the DCM. See Section 2.4, “Connecting to a local network” for full details. Once you have connected the DCM to your local network or to the Internet, you can use a wide range of methods to retrieve data from it. • All DCM units feature an
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CMG-DCM 2 Installing the CMG-DCM 2.1 Overview The DCM is effectively a low-power Linux computer dedicated to seismic data flow tasks. Resources permitting, the DCM can perform any computational task you require. Because of this flexibility, the DCM must be configured for your particular purposes before it can be used: 1. If you only need to use the DCM as a data store, you can gain console access over the serial port for configuration. 2. If you are going to use the DCM as part of a TCP/IP n
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Operator's guide A rack-mounted DCM has a separate POWER IN connector on the back panel, which should be attached to a 12 V DC supply. There is also a POWER OUT connector on this panel, which allows you to daisy-chain several DCM units together. The POWER OUT connector is provided merely for convenience: lines from the POWER IN connector pass straight through. An integrated DCM receives its 12 V DC power from two pins in its single connector. See Appendix A, “Connector pinouts” for the posi
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CMG-DCM 5. You now have access to the DCM's console and all of its functions. You should change your password, if you have not done so already, with the command passwd For full details on how you can configure the serial ports of the DCM, see Section 4.3, “Serial port configuration”. Connecting over Ethernet You can use a “crossover” Ethernet cable to connect the DCM directly to your computer. This has the same effect as connecting the DCM and your computer to a separate hub using standard
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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
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CMG-DCM 2.4 Connecting to a local network The DCM is normally supplied with a 10BaseT Ethernet port. This port can be used to connect to your local network. When the DCM starts up, it will try to find a DHCP server on your network to assign it an IP address. If you use DHCP on your network, and you want to access the DCM's Web server or console over the network, you may be able to find out from the DHCP server which address it has given the DCM, in which case you can access it directly. Oth
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Operator's guide If you are connecting the DCM to a machine on the same network, you do not need to configure any more options at this stage. If your network uses DHCP, you will not need to perform this step. Instead, ensure the DCM is also using DHCP with gcfgdbset net.eth.0 dhcp/bootp 5. Issue the command ifconfig The DCM will reply with technical information on its current network setup. Each interface is listed separately. The NETWORK port uses the interface eth0: eth0 Link encap:Et
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CMG-DCM The options will take effect immediately whenever possible. Some changes may take some time to complete, since services may need to be restarted. The gcfgdbset command performs only simple checks on the new value, so you should check the syntax of the option carefully. Wi-Fi Optionally, a DCM may be supplied with 802.11 (“Wi-Fi”) hardware in place of Ethernet. There are two modes in which an 802.11 network may operate: • In ad hoc mode, data packets are sent out over the wireless con
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Operator's guide of intermediate machines which support SSH. Once this chain is set up, you can treat the connection as if it were a direct link between the DCM and your computer. Many standard Internet protocols may be fed through SSH in this manner. Whether this is possible will depend on the precise configuration of your local area network. For more details, please see the documentation for SSH clients such as ssh and putty. 2.5 Connecting digitizers and external hardware The DCM is desi
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CMG-DCM gives you access to all the module's configuration options. You can use this Web interface over any network connection using the HTTP or HTTPS protocols. Alternatively, you can log in to the DCM's Linux operating system and issue commands directly: see Section 6.2, “Command line tools”. Web setup The DCM provides a Web interface which you can use to set up the system. To access this from anywhere on the local network, open any web browser and navigate to the IP address of the DCM. F
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Operator's guide current contents of the on-board Flash memory. The links in the menu on the left lead to various pages where you can change the configuration of the DCM. Initially, you should be sure to change your administrator password. Click on Administrators under Network configuration, fill in the new password in the two text boxes below Existing accounts, near the bottom of the page, and click Change password. If you want to add any other named accounts, you may do so at this stage (
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CMG-DCM A useful feature of Güralp Systems digitizers is the ability to output streams at several data rates. Each stage of filtering is known as a tap, producing data at a particular rate. At each tap, incoming data is filtered and its data rate reduced by a user-selectable factor of 2, 4, 5, 8, or 10 (in the case of Güralp DM24 digitizers). The data rate at each tap must be an integer number of Hz. For a full listing of the possible tap configurations, see Section 5.2, “Digitizer Setup”.
