Rockwell Automation 1771-DB BASIC MODULE - Manual (Page 108)

Chapter
Data Types 8
8 -8
3.3-Digit, Signed, Fixed Decimal BCD
This value requires two words of the processor data table. The first word
contains the overflow, underflow, sign data and the three most significant
digits of the value. The second word contains the lower three digits of the
value. The value ranges from –999.999 to +999.999. If an overflow or
underflow condition exists, a value of 000.000 is reported and the
appropriate bit is set. Any digits more than 3 places to the right of the
decimal point are truncated. See CALL 26 (page 12 -17) and CALL 39
(page 12 -38).
17 16 15 14 13 12 11 10 07 06 05 04 03 02 01 00
not used
underflow bit (1 = value smaller than + .001 (ie. .0002)
sign bit (1 = negative; 0 = positive)
overflow bit (1 = value > + 999.999)
Integer Portion of Value
15036
D6 D5 D4
Word 1
–
17 16 15 14 13 12 11 10 07 06 05 04 03 02 01 00
D3 D2 D1
Word 2
Fractional Portion of Value
not used
implied
decimal point
–