Rockwell Automation 1772-AF4,D17726.5.3 User Manual, AUX FUNCT PROM - Manual (Page 19)

Programming
Chapter 3
3Ć11
2. Enter 01, the function number for AF4 addition.
This entry identifies that the function entered is to perform an AF4 addition and
that the processor use the data table format shown in Figure 3.2 when executed.
Operands 1 and 2 represent the two 6-digit numbers we wish to add. The six
digits of operand 1 are represented in BCD by the groups of bits labeled digit 1
through 6. Digit 1 and digit 6 are the most significant and the least significant
digits respectively. This digit labeling system also applies to operand 2 and the
result.
Figure 3.2
General AF4 Addition Function Word and Digit Format
17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 0
S
Digit 1
(MSD)
Digit 2 Digit 3
Bit No.
Data Address
m
Digit 5
Digit 6
Digit 4
(LSD)
Operand 1
S
Digit 1
(MSD)
Digit 2 Digit 3
Digit 5
Digit 6
Digit 4
(LSD)
Operand 2
S
Digit 1
(MSD)
Digit 2 Digit 3
Result Address
n
Digit 5
Digit 6
Digit 4
(LSD)
Result
D ER E
m + 1
m + 2
m + 3
n + 1
E = Enable Bit (1 = Function in Progress)
S = Sign Bit (1= Negative)
D = Done Bit (1 = Function Complete)
ER = Error Bit (1 = Overflow)
MSD = Most Significant Digit
LSD = Least Significant Digit
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