PSN-L Email List Message

Subject: Re: Drum plotter for Dataq users
From: John Lahr johnjan@........
Date: Fri, 19 Apr 2002 22:37:02 -0600

Hi Bob,

This sounds like a great program.  I would like to try it out with your test data.

I don't have a DI-194, but do have the DI-154 unit.  Do you think it will work with this
format as well?  I think the 12 bit AD will be helpful, although the price is $150
(100 with an educational discount).


At 11:15 PM 4/19/2002 -0400, you wrote:
Hi everyone,

  Since I would enjoy having others appreciate and enjoy the fruits of my recent hard labor, I am offering to share free my drum plot program with others having the same hobby.  I warrant that the program is not malicious, but will take no responsibility if fails to live up to your expectations.  It does fully live up to mine, and has proved to be very useful. With its built-in filters, I can record teleseisms of magnitude 6.5 or more, and accurately reproduce L waves of 24 seconds period, even though my antique Strengnether seismometer has a natural period of only 3.5 seconds.

 This VisualBasic6.0 program presents seismic data in a 24hr format, starting at the first hour recorded, using WDQ files recorded by Dataq hardware and software (DI-194 Acquisition).  The format is very similar to that seen on the LDEO-LDSN Data Repository website: l

 An expanded plot capaibility is provided, the starting time determined by a mouse click on the desired time on the drum p lot.  Filtered copies of the original file can be saved by a mouse click.  Filter options include high pass, smooth, long period, and broadband, with user controlled filter parameters.  For most accurate long period and broadband response, the user must input the period and damping of the sensor.

 A most useful feature of this program is its ability to display filtered seismic data as the raw data is being recorded.& nbsp; When a file currently open for recording is selected,  the drum plot is updated as often as new data is recorded to the file (every 256 data samples).  The user has almost instant knowledge of a seismic event when it occurs.  The abi lity to examine the detailed waveform plot is retained as well.

 This program is not available in installable form.  Simply run the file as is.  It usually will run without req uiring more system files on Windows98 or later.  Using my sample files, you won't even need the Dataq hardware and softwar e to try it out.  You can order the A/D board and WindaQ Lite software from for about $15.  You will need a very stable low-pass DC amplifier delivering at least +-4.5v to drive the DataQ board.

 Matching this program up to the characteristics of your particular sensor and sampling rate may require some program chan ges, which I am willing to do for you.  I could also adapt this program to read any other data file format.

 If you have an interest, please e-mail me for a more detailed description of the program.  Also, describe what equip ment you are using.  If you have any experience in VisualBasic programming, say so.  I might want to give you the sou rce code, so I won't have to help you every time you need it.

Bob McClure

John C. Lahr
1925 Foothills Road
Golden, CO 80402
Phone: (303) 215-9913 

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