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Pacific Data Recorder New Format

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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[8];            /* Channel name               */

char    desc[20];          /* Channel description        */

char    loct[20];          /* Gage location              */

char    units[14];         /* Engineering units          */

char    datetime[19];      /* Time and date channel

                              was saved                  */

char    sernum[13];        /* Gage serial number         */

char    model[15];         /* Gage model                 */

char    range[8];          /* Gage range                 */

char    cable[5];          /* Instrumentation cable

                              number                     */

char    testname[40];      /* Test name                  */

char    testloc[20];       /* Test location              */

char    operator[20];      /* Instrumentation technician */

short   channel;           /* TDR number                 */

short   caltype;           /* Automatic (1) or

                              Simulated (2) Cal          */

short   trigenable;        /* Internal trigger enabled=-1,

                              disable=0                  */

short   numpre;            /* # of pretrigger segments   */

short   numpost;           /* # of posttrigger segments  */

short   rate[15];          /* Rate in microseconds for

                              each segment               */

short   memsize;           /* TDR memory size in KB      */

float   val1;              /* Cal baseline in engineering

                              units                      */

float   val2;              /* Cal step in engineering

                              units                      */

float   svolts1;           /* Cal baseline in volts      */

float   svolts2;           /* Cal step in volts          */

float   poly1;             /* Conversion polynomial

                              offset                     */

float   poly2;             /* Conversion polynomial scale

                              factor                     */

float   triglevel;         /* Trigger level in

                              millivolts                 */

float   ca;                /* Gage CA                    */

float   re;                /* Gage RE                    */

float   rx;                /* Gage RX                    */

float   rg;                /* Gage RG                    */

float   tworl;             /* Cable line resistance      */

float   pred;              /* Engineering prediction     */

float   rc;                /* Actual cal resistor used   */

double  strttotrig;        /* Start to trigger time      */

short   prate;

float   gain;

float   sensitivity;

char    projectname[40];

char    dummy[1690];

} HEADER;

Files produced using this format are always 264,192 bytes in size. The header block (shown above) begins at the start of the file, and is followed (at offset 2048) by 16 segments of 8192 2-byte integers representing voltages (the last block of 16384 bytes is not used by DPlot). The time step for each segment (in microseconds) is taken from the rate member of the header.

Raw voltages are translated to engineering units by:

Volts = float(RawData)/32768.;

Y = Header.poly2 * Volts + Header.poly1;

 

 


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