May 22, 2019

Grinder - Data files

During a casting, a collection of data files accumulate in the pilot home directory. These are IRAF image files, for better or worse. Don't be fooled into thinking these are some kind of image. The contain lines of data, with a new line being added every minute. There are 8 sorts of files, as follows: 
cd pixels
ls -l *190501*
-rw-r--r-- 1 tom tom  382464 May  1 23:59 adcv190501.pix
-rw-r--r-- 1 tom tom  123392 May  1 23:59 etmp190501.pix
-rw-r--r-- 1 tom tom 2213888 May  1 23:59 hpwr190501.pix
-rw-r--r-- 1 tom tom 2213888 May  1 23:59 htmp190501.pix
-rw-r--r-- 1 tom tom  831488 May  1 23:59 jtmp190501.pix
-rw-r--r-- 1 tom tom 4425728 May  1 23:59 ttmp190501.pix
-rw-r--r-- 1 tom tom  123392 May  1 23:59 zsct190501.pix
-rw-r--r-- 1 tom tom  123392 May  1 23:59 ztmp190501.pix

imheader *190501* lo+

adcv190501.imh[66,1440][real]: adcv190501
etmp190501.imh[21,1440][real]: etmp190501
hpwr190501.imh[300,1440][real]: hpwr190501
    Line storage mode, physdim [384,1440]
htmp190501.imh[300,1440][real]: htmp190501
    Line storage mode, physdim [384,1440]
jtmp190501.imh[144,1440][real]: jtmp190501
ttmp190501.imh[720,1440][real]: ttmp190501
    Line storage mode, physdim [768,1440]
zsct190501.imh[21,1440][real]: zsct190501
ztmp190501.imh[21,1440][real]: ztmp190501
In general, the "line storage mode" matches the image dimensions, but exceptions are noted above in 3 cases.

All of these files have 1440 columns, which is 24*60 = 1440, so there is one column (line) per minute. The amount of data in each line depends on the sort of file it is, and what indexes the data depends. As an example, for the "z" (zone) files, there can be 21 zones and that is what you get, zones 0-20. "Pixels" in these files are 4 byte single precision floating point values.

Note that the oven software defines a marker for non-existant data: 

#define INDEFT  (1.6e38)

IRAF considers this a perfectly good data value, so be aware.

Have any comments? Questions? Drop me a line!

Tom's home page / [email protected]