FORMAT OF MAXX TEST PROGRAMS
If you plan to write your own file conversion routines to combine FEC data-log and program files in your own format, there are a few more bits of info you could use.
To associate a reading in the data file with its corresponding test, just read the sequence number (n) from the data file then find its corresponding test as follows.
Offset into test program for test n is 28* (n-1) + 354. The 28 bytes at this location fully describe this test.
To interpret a 28 byte test spec, first convert the non-zero 1st byte to the name of the test. Next we suggest you look at byte 10 of the 28 byte block to get the scale byte of the reading. The DATA VALUES at offsets 1 and 4 are forcing values if the digits are non-zero and the scale bytes do not match that byte found at offset 10.
If the maximum limit is -2 on any scale, that is a “must pass” or “no limit”.
A soak time of 0 for a VF test means 300µS. You should not encounter zero soak time on any other active tests.
If bit 15 of the digits part of a reading is true, that reading failed the test limits.
If bits 2-6 of the scale byte in a reading are true, that reading is invalid. That could mean that it is “offscale”. There are other possible reasons for invalid readings, so it would be useful to choose scales so that all valid readings would be on the scale.
Unfortunately not all offscale readings are marked invalid as of this writing. It would probably be a good idea to maintain a table of fullscale readings for each type of test.
A binary “PROGRAM” for MAXX uses 3072 bytes assigned as follows.
b represents a byte of data
$$ means ASCII string
c$ means ASCII string preceded by a count byte
dv means FEC “DATA VALUE” which see
Bits are labeled 0-7 or 0-15
Other codes may be assigned in the future.
| OFFSET | DATA | EXPLANATION |
|---|---|---|
| 0-1 | CCCCh | Identifies a standard MAXX PROGRAM |
| 2-18 | c$ | Counted TITLE (count + 16 characters) |
| 19-97 | c$ | Counted DESCRIPTION (count + 78 characters) |
| 98-353 | $$ |
(Unused characters in each title are blanks) |
| 354-2453 | ---- | 75 test specs at 28 bytes per test (see details below) |
| 2454 | FFh | Marks end of test specs |
| 2455-2774 | ---- | 32 sort specs. At 10 bytes per sort. (See detail below) |
| 2775-3068 | ---- | Reserved |
| 3069-3070 | bb | Value in volts for voltage limiter |
| 3071 | b | Code for type of D.U.T. |
| 0 = STD (normal diode) | ||
| 1 = TCZ | ||
| 2 = BIPOLAR | ||
| 3 = MSV | ||
| 4 = THY |