This file format is frequently used in field tests with Pacific Data recorders.
These files consist of a header block followed by data representing measured voltage. The header structure used in these files is defined below:
typedef struct tagHEADER {
char tag_name[8];
char units[4];
char channel_description[20];
char channel_location[20];
char not_used_12[12];
char file_test_name[40];
char file_creation_date_and_time[24];
short trigger_timeout_value;
short number_of_pretrigger_segments;
short number_of_posttrigger_segments;
short sample_rate_profile[16];
short configuration_word;
short number_of_raw_data_files_in;
short auto_calibration_procedure;
short auto_calibration_order;
short internal_trigger;
char not_used_80[80];
float convert[4];
float trigger_level;
float correlation_data[48];
float calibration_conversion[10];
float reserved;
} HEADER;
Files produced using this format are always either 263,936 bytes or 526,080 bytes (Modar model 5700 only) in size. The header information starts at offset 1024 from the start of the file. Information preceding the header is not used by DPlot. Raw data is organized in 16 segments of either 16384 bytes or 32768 bytes (Modar model 5700 only) beginning at offset 1792 in the file. Each segment may have a different time step, which is determined (in microseconds) by:
float time_mlpy[16] { 32768., 16384., 8192., 4096.,
2048., 1024., 512., 256.,
128., 64., 32., 16.,
8., 4., 2., 1. };
float Modar_time[16] {100000., 50000., 20000., 10000.,
5000., 2000., 1000., 500.,
200., 100., 50., 20.,
10., 5. 2., 1. };
for(i=0;i<=15;i++) {
if( i < Header.number_of_pretrigger_segments )
k = 0;
else
k = i - Header.number_of_pretrigger_segments + 1;
if( ModarFile )
TimeStep[i] = time_mlpy[Header.sample_rate_profile[k]];
else
TimeStep[i] = Modar_time[Header.sample_rate_profile[k]];
}
Raw data is translated to engineering units by the cubic polynomial:
volts = float( RawData ) / 3276.8;
Y = ( ( Header.Convert[3]*volts +
Header.Convert[2] )*volts +
Header.Convert[1] )*volts +
Header.Convert[0];
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