The program NDDown20 is a Windows 95 program that downloads geophysical data from the Geoscan FM36 gradiometer and RM15 resistivity meter. The program was developed for use by students in the University of Notre Dame archaeology field school and is being made available free to anyone who might like to evaluate or use it. The Windows 95 version of NDDown is more reliable than the Windows 3.x version and has several enhancements. A compressed version of the program (nddwn20z.exe) can be obtained by any one of these methods: 1. Visiting the ND Download web page at http://www.nd.edu/~mschurr/nddown/ 2. Sending $10 US for handling and shipping to the author (below). 3. Sending two blank 3.5 inch inch diskettes and a self-addressed, stamped diskette mailer to the author. To use the program, uncompress the zipped version of the program by running nddwn20z.exe. Then run the program Setup.exe. The setup program will install NDDown20 in whatever directory you select and will add the program to the program menu. NDDown requires several Visual Basic 5.0 files in order to run. The set-up program will automatically install these on your computer. If any of the required files are already on your system, you may be asked if you want to replace them. I recommend that you use the most recent version. The program NDDOWN20.EXE can be run from the Program list or by double-clicking on its icon. Notes on Using the Program: The operation of NDDown is largely self-evident. Just select the desired parameters and press the Download button to begin downloading. The program will instruct you when to press the "Dump" button on the instrument. Some comments on program operation may be useful to first-time users: PARAMETERS: Instrument: Select either RM15 or FM36. Selecting RM15 disables the gradiometer drift button. Site: Type in a name or code to identify the site. The site name will become the first 7 letters of the filename used to save the grid file, and to allow grid files to be compatible with Windows 3.x or DOS files, the site name box does not allow the user to enter characters that will produce illegal DOS file names. You can always change the file name to a long file format accepted by Windows 95 when you save the file. Grids: Up to eight grids can be downloaded at one time. If you enter more points than the FM36 or RM15 can hold, you will be invited to revise your selection. Grid Sizes: 10 and 20 m grids are supported. The grid can be square or rectangular. Sample Interval: Sample intervals of 1, 2, 4, and 8 points per meter are supported Transect Interval: Transect intervals of 1, 2, and 4 samples per meter are supported. Gradiometer Drift: If the drift box is checked, a drift correction will be applied to the data. A drift correction is not usually applied to data collected using zig-zag traverse modes, so you will be asked to verify your selection if you want to drift-correct zig-zag data. The FM36 logs drift points based on the grid size and the transect interval. For example, if the grid size is 20 meters and the there are 4 transects per meter (a 0.25 m transect interval), the gradiometer will demand that a drift point be logged every 20 transects (or every 5 meters). For a well-balanced gradiometer, there is no need to log a drift point this often, and NDDown only uses the last drift point of the grid for the drift correction. NDDown assumes that the drift reference point was the first point in the survey. In order to properly use the drift correction, be sure to log your last drift point of each grid over the first point that you surveyed. The program will report the drift for each grid and give you the opportunity to use or decline the drift correction. IMPORTANT: Set the baud rates for the RM15 at 9600. A baud rate of 2400 is assumed for the FM36. Use the "NO SPACE" option for data spaces on the RM15. Attach the instrument to COM1. Close any other programs that might interfere with the download. For safety, I recommend closing all other programs. DOWNLOADING: Once the parameters are selected, click on the "Download" button. The program will prompt you when to press "Dump" on instrument. Make sure that you press "Dump" on the instrument AFTER you press "OK" as instructed by the program. Pressing "Dump" before "OK" will result in lost data and an unsuccessful download. The grid and points counter boxes will show which point is being read. If the boxes remain blank or do not change, check the connections and try again. Once downloading has begun, it can only be canceled by killing the program (CTL-ALT- DELETE keys). This is because the Geoscan instruments do not support handshaking. A cancel button could lead to data loss because it could permit other programs to take control of the system. You will be prompted when downloading is complete. You will then have the opportunity to save additional information about each grid and a file name to save it under. If you cancel the file save operation for any grid, the program will skip that grid. FILE FORMATS: The data are saved as an ascii datastream with one point per line. A 15-line header contains information about the grid in a comma-delimited format. Sample RM15 header: ND_Download, Instrument, RM15 Site, 12mr231 Date, 05-27-1997 Time, 16:57:33 E-W Grid Size (m), 20 N-S Grid Size (m), 20 Transect Interval (per m), 1 Sample Interval (per m), 1 SW Grid Corner - E Coord, 1010 SW Grid Corner - N Coord, 960 Probe Array, Dipole Probe Spacing(m), 0.5 Traverse Mode, Zig-Zag (corrected) Comments, sample file header Sample FM36 header: ND_Download, Instrument, FM36 Site, 12mr231 Date, 05-27-1997 Time, 17:19:34 E-W Grid Size (m), 20 N-S Grid Size (m), 20 Transect Interval (per m), 2 Sample Interval (per m), 4 SW Grid Corner - E Coord, 970 SW Grid Corner - N Coord, 960 Traverse Mode, Parallel Drift Correction, None Averaging, None Comments, sample file header SAVING AND RETRIEVING SURVEY METHODS: You can save and retrieve survey methods under the "Method" menu. The method is just a simple ascii file that contains information about the survey conditions (grid size, intervals, etc.). This is convenient if you have some standard surveys because you do not have to manually enter the survey parameters each time. Saving a method saves the current NDDown settings in the file name of your choice. The program also creates an "INI" file in the Windows directory that saves whatever settings are present when the program is exited normally. Thus, there is no need to re-enter parameters or retrieve a method file if you want to use the same settings that you used in your last NDDown session. If the "INI" file is not present for some reason, NDDown will use default settings. It will generate an error message when you exit the program if there is no Windows directory available. EXITING THE PROGRAM: Click on "Exit" under the "File" menu. VERY IMPORTANT: The user assumes all risks and liabilities associated with any use of the software. If you are not willing to accept this condition, destroy your copy of the software immediately. Send questions, reports of bugs, pleadings for enhancements, etc. to: Mark.R.Schurr.1@nd.edu Mark Schurr Department of Anthropology University of Notre Dame Notre Dame, IN 46556