Rockwell Automation 1771-DB Basic Module User Manual - Series A - Manual (Page 144)

Data Types
Chapter 7
7–2
This value requires one word of the processor data table. The data is
represented by a 3-digit binary coded decimal integer (figure 7.2).
Overflow, underflow and sign are also indicated. An underflow or
overflow condition sets the appropriate bit and a value of 000 is returned.
The value ranges from -999 to +999. Fractional portions of any number
used with the routine are truncated.
Figure 7.2
Truncated 3-Digit BCD Integer
This value requires one word of the processor data table. The data is
represented by a 4-digit BCD integer (figure 7.3). The value ranges from
0-9999. There is no indication of sign, underflow or overflow. However, if
a value of greater than 9999 is converted, the value reported is 0000.
Fractional portions of any number used with the routine are truncated.
7.2.2
3-digit, Signed,
Fixed Decimal BCD
7.2.3
4-digit, Unsigned,
Fixed Decimal BCD