On startup, slink2ew reads the configuration file named on the command line. Commands in this file set all the parameters used for configuring the Earthworm SeedLink client module. In the control file, lines may begin with a valid slink2ew command (listed below) or with one of 2 special characters:
Command names must be typed in the control file exactly as shown in this document (commands are case sensative). Blank lines are also permitted in the control file.# marks the line as a comment (example: # This is a comment).
@ allows control files to be nested; one control file can be
accessed from another with the command "@" followed by
a string representing the path name of the next control file
(example: @model.d).
Below are the commands recognized by slink2ew, grouped by the function
they influence. Most of the commands are required; they may be
specified in any order in the control file.
Earthworm system setup:
MyModuleId required
RingName required
HeartBeatInterval required
Verbosity optional
SeedLink server and connection parameters:
SLaddr required
SLport required
Selectors optional
Stream optional
NetworkTimeout optional
NetworkDelay optional
KeepAlive optional
MaxRate optional
WriteMSEED optional
SLRecSize optional
instId optional
Output control:
LogFile required
StateFile optional
StateFileInt optional
In the following section, all configuration file commands are listed in alphabetical order. Listed along with the command (bold-type) are its arguments (in red), the name of the subroutine that processes the command, and the function within the module that the command influences. A detailed description of the command and is also given. Default values and example commands are listed after each command description.
command arg processed by in function
MyModuleId mod_id ReadConfig Earthworm setup
Sets the module id for labeling all outgoing trigger, heartbeat, and error messages. mod_id is a character string (valid strings are listed in earthworm.d) that relates to a unique single-byte number.
Default: none
Example: MyModuleId MOD_SLINK2EW_GE
RingName ring ReadConfig Earthworm setup
Indicates which shared memory region to use for waveform output. ring is a character string (valid strings are listed in earthworm.d) that relates (in earthworm.d) to a unique number for the key to the shared memory region.
Default: none
Example: RingName WAVE_RING
HeartBeatInterval interval ReadConfig Earthworm setup
Defines the interval in seconds at which the module will issue TYPE_HEARTBEAT messages.
Default: none
Example: HeartBeatInterval 30
Verbosity level ReadConfig Earthworm setup
Specifies the level of logging verbosity. Level 0 is rather quiet and mostly reports errors, level 1 shows negotiation details and every received packet and level 2 shows a lot of details.
Default: 0
Example: Verbosity 0
SLaddr address ReadConfig SeedLink parameters
Specify the address of the SeedLink server. This can be either on IP address (four period-separated numbers) or the domain name of the server.
Default: none
Example: SLaddr rtserve.iris.washington.edu
SLport port ReadConfig SeedLink parameters
Specifies the IP port number for the SeedLink server. This is commonly 18000.
Default: none
Example: SLport 18000
Selectors selectors ReadConfig Data selection
Specify the SeedLink selectors for uni-station mode or default selectors for multi-station mode. Multiple selectors must be enclosed by quotes. If Stream commands are also specified in the command file, implying multi-station mode, any selectors specified with this command will be used as defaults when no data stream selectors are specified with a given Stream command.
Default: none
Example: Selectors "BH?.D LH?.D"
Stream streamkey [selectors] ReadConfig Data selection
Specifies one stream of data to be requested from the remote SeedLink server. This command implies the use of multi-station mode and can be specified multiple times to requested multiple data streams. The streamkey is composed of a network and station code separated by an underscore. Optional SeedLink selectors may be specified after the stream key. Multiple selectors must be enclosed in quotes. Beware of collecting multiple data streams with the same station code and differing location codes as the rest of Earthworm does not know about location codes, so the two data streams would get mixed together with bad results.
Default: none
Example: Stream GE_DSB "BH?.D HH?.D"
NetworkTimeout timeout ReadConfig Earthworm setup
Sets the network timeout in seconds. If the module has not received any packets from the remote SeedLink server in this amount of time the connection will be closed and re-opened if possible. A value of 0 disables this feature.
Default: 600
Example: NetworkTimeout 300
NetworkDelay delay ReadConfig Earthworm setup
Sets the re-connection delay in seconds. After the connection to the remote SeedLink server has been broken (network timeout or any other connection problems) the module will wait this many seconds before attempting to re-connect.
Default: 30
Example: NetworkDelay 10
KeepAlive interval ReadConfig Data Selection
Specifies the interval in seconds that the module will send keep alive (heartbeat) packets to the remote SeedLink server. A value of 0 disables the feature. This feature only works with versions of SeedLink 2.93 or greater. This is useful for keeping a network connection open that might be closed by itermediate firewalls/gateways when the data stream only flows at intervals.
Default: 0 (disabled)
Example: KeepAlive 600
MaxRate rate ReadConfig Earthworm setup
Specifies the maximum rate in bytes per second that the module will receive data and generate TraceBuf packets. A value of 0 disables the feature. This is useful for limiting the rate that TraceBuf packets are forwarded to the local system. In particular, during times of backfill data may be delivered by the upstream server faster than the local system can process the packets.
Default: 0 (disabled, no rate limit)
Example: MaxRate 204800 (i.e. 200 kilobytes/second)
WriteMSEED switch ReadConfig Earthworm setup
Sets the switch to control whether MSEED message types will be sent to the transport ring. By default, the module will create TRACEBUF2 messages.
Default: 0 (disabled)
Example: WriteMSEED 1
SLRecSize bytes ReadConfig Earthworm setup
Sets the miniSEED record size in bytes expected from the SeedLink server. The standard record length for SeedLink is 512-bytes. In specialized cases SeedLink servers can be configured to transmit other record sizes such as 256 or 128 bytes (usually to reduce the data latency), slink2ew must be configured to match the record length expected.
Default: 512
Example: SLRecSize 256
instId ID ReadConfig Earthworm setup
Override the installation ID included in TraceBuf packets. By default the installation ID is that of the local system as defined by the EW_INSTALLATION environment variable. This option is useful for specifying the installation ID of the remote system providing the data or simply to avoid inserting the local ID.
Default: (Local Installation ID)
Example: instId INST_UNKNOWN
LogFile switch ReadConfig Earthworm setup
Sets the on-off switch for writing a log file to disk. If switch is 0, no log file will be written. If switch is 1, coaxtoring will write a daily log file(s) called coaxtoringxx.log_yymmdd where xx is coaxtoring's module id (set with MyModuleId command) and yymmdd is the current UTC date (ex: 960123) on the system clock. The file(s) will be written in the EW_LOG directory (environment variable). If switch is 2 the log file is written but output to stdout and stderr is suppressed.
Default: none
Example: LogFile 1
StateFile [filename] ReadConfig Earthworm setup
If this flag is specified a file with a list of sequence numbers is written, during a clean module shutdown, to the parameter directory with the name "slink<mod id>.state". Alternatively, a filename may be specified. During module startup these sequence numbers are used to resume data streams from the last received data. In this way continuous data can be collected even through system restarts. If this flag is not set the module will always request the next available data. Using this functionality is highly recommended unless you know that it is not necessary.
Default: none
Example: StateFile
StateFileInt interval ReadConfig Earthworm setup
This option specifies the interval for saving the state file in number of packets received. In otherwords, using the default interval of 100, the statefile will be updated every 100 packets received. The purpose of this functionality is to minimize the amount of duplicate data collected if the module is ever killed without saving the current state information.
Default: 100
Example: StateFileInt 500
SeedLink data transfer, all/uni-station and multi-station mode
The SeedLink protocol allows two different modes of data transfer. All or uni-station mode is the method used for transmitting all stations from a node. In this case the client does not specify a stream key (network and station code) as the data stream is implied to be whatever is available from the server. Multi-station mode is the method used for requesting multiple, selected data streams (stations).
For slink2ew the presence of one or more Stream commands in the configuration file triggers multi-station mode. Otherwise the module defaults to all/uni-station mode.
SeedLink selectors
SeedLink selectors are used to request specific types of data within a given data stream, in effect limiting the default action of sending all data types. A data packet is sent to the client if it matches any positive selector (without leading "!") and doesn't match any negative selectors (with a leading "!"). The general format of selectors is LLSSS.T, where LL is location, SSS is channel and T is type (one of [DECOTL] for Data, Event, Calibration, Blockette, Timing, and Log records). "LL", ".T", and "LLSSS." can be omitted, implying anything in that field. It is also possible to use "?" in place of L and S as a single character wildcard. Multiple selectors are separated by space(s).
Some examples:BH? - BHZ, BHN, BHE (all record types)For slink2ew only data records will be written to the ring. In other words, requesting any records in addition to data records is a waste and you should always append ".D" to any specified selectors.
00BH?.D - BHZ, BHN, BHE with location code '00' (data records)
BH? !E - BHZ, BHN, BHE (excluding detection records)
BH? E - BHZ, BHN, BHE & detection records of all channels
!LCQ !LEP - exclude LCQ and LEP channels
!L !T - exclude log and timing records
SeedLink selector examples
#Selecting a two specific stations and a sub-set of their channels Stream GE_DSB "BH?.D HH?.D" Stream II_KONO 00BH?.D # Wildcards can be used with servers that support them, get all TA network stations Stream TA_*