| RESPONSE(1) | SCEC Utilities | RESPONSE(1) |
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response is a program designed to produce a PostScript file describing the characteristics of a single seismic component. The PostScript file will produce a single page sheet when printed.
The sheet can be thought of as being composed of five different sections.
section two consists of general information that is provided by the owner or manufacturer or calculated from manufacturer values. Owner provided values would be damping resistor values (Rdeo, Rdsr1, Rdsr2) and model information.
section three consists of measured and calculated values from the LLNL program id. This program provides three values: Free period, Damping, Gain. All of these values are passed through to the output file. The last of the three is used to calculate the damped generator constant (Gid) and, if sensor damping information is available, the undamped generator constant (Guid).
section four consists of three or four plots depending on what information is available. The plots graphically describe the response characteristics for the sensor component. If the sac data files are available for the recorded and modeled step response, those are overlayed on each other in the fourth plot. This overlay provides the user with a means of seeing how accurate the modeled step response is.
section five shows the usage of this information in the transfer subroutine of the LLNL program SAC. This shows how the provided information can be used to deconvolve recorded data back to ground motion. This section also contains information about the analytic transfer function.
Information displayed on the sheet is provided through a free form information table(s) input to response via the -info command line arg.
The way the input files work is that the first file establishes the base entries. All subsequent info files will try to merge info with the base entries. Matches are attempted in the following combinations. filename only owner, model only with no filename or serial number defined model only with no filename, serial number, or owner defined. If an entry matches one of these combinations, ALL supplied fields from the new entry will be written to the base entry, overwriting existing fields as needed. This method of information collection governs the order that users should provide the info to response.
The first info file is expected to be the output table from id.csh. This provides a filename and some calculated values (that should not be input from other files). Additional input files should start from very generic information and work towards specifics. Typically users may want to have a file containing generic information about a given sensor around. This file would go first after the table file that establishes the base information. Next could be a file that contains specific variations from the generic information by owner. These files can be obtained from the PBIC. The information observed by the operator should come last and should have specific values for Iext and possibly Rmeas.
The Mass weight (mass) (in Kilograms) is the only manufacturer information required to calculate the Generator constant from id. The other two pieces of information required for calculation of Gid, are the externally measured current from the Calibration box (Iext) and the Gain value calculated by id (GNid). If Iext is not provided, but Vext and Rmeas are, then those values are used to calculate Iext. Rmeas is the resistance of the entire sensor array (including damping) and Vext is the measured voltage applied across the entire sensor array to produce the calibration pulse.
The easiest way to build the information table is to use a spreadsheet program and export a tab delimited file. Any line whose very first character is a "#" indicates a comment in the information file. The first non-comment line is taken to be the header line that will contain the field headings. Although not yet implemented, the -help option will, at some point, provide the accepted field headings for the file. field headings are case insensitive and usually correspond to the variable names mentioned here and in other documentation (Iext, Gnid). Other common values are: Mass, ser (for serial number),Rdeo (damping resistor).
Information not available from the information tables is designated on the output sheet with the tag "N/A".
The SAC step response file name should have the following components (in the specified order) in the pathname.
The input table is generally the file produced by id.csh. It contains the name of the file and the three valued produced by id. If no input filenames are provided on the command line, response assumes that all files in the input file are to be processed. Otherwise, only filenames whose base names match (up to the final ".") will be processed.
/local/ucsb/bin/response
If table has multiple entries for a given sensor and the table is the only used input, Some values (specifically Rdeo) may be corrupted and contain different values.
Maximum number of info files that may be specified on the command line is 5. If this number is exceeded, program will probably bomb.
Error checking on field loading of info files is not very extensive.