Data Logging Formats

contributed by Bob Lash (BAMBI.net)

After many years the first SARA data recording format was agreed upon at the 1991 conference. This article is intended to record the characteristics of various formats such that reviewing old computer data will be simplified.

You do not have to store your data in the current format, but if you share data with other members you should write a translator program to put the data in the required format. If you are writing your own logging or plotting programs, this should not be difficult. If you develop a new format, be sure to take the time to describe the format in detail.

Most formats will only handle simple drift scan type recordings, this is the equivalent of chart recordings. More complex formats can be developed using the SARA 1991 format as a base. The SARA1991 header on the file tells what format to expect the data that follows. The header ID should be protected as a "key" to the format that follows.

I suggest that all data be stored in ASCII text files. This is inefficient but a simple way to examine data. The use of Pkzip, Stuffit and other file compression programs will allow the transfer of data in an efficient manner. When transferring data via modem do not confuse ASCII text data with the ASCII text file transfer method. Use XModem or the equivalent to transfer your ASCII text file. Data when shared via floppy disk can be sent on any format compatible with the persons sharing data. An Ms-DOS 1.44 meg format is suggested. For Macintosh users having the 1.44 meg disk drive, reading and writing the Ms-DOS floppy should be no problem.

It is important to set your computer clock to GMT time and read the clock to determine when to save a sample. This prevents cumulative errors that occur if a timing loop is used to select samples. Putting data points in a range of 0 to +32767 gives adequate resolution and is within the range of integer values for most computer languages.

Download SARA Data Logging Formats courtesy Chuck Forster (11 kByte PDF)