Rockwell Automation 1772-AF4,D17726.5.3 User Manual, AUX FUNCT PROM - Manual (Page 53)

Programming
Chapter 3
3Ć45
3. Enter a data address and a result address.
If we choose a data address of 200 and a result address of 305, the AF4
establishes the data table format shown in Figure 3.44. The data address
eventually contains the most significant three digits of the operand (the number
whose reciprocal we seek). The next higher address, word 201, is reserved for
the three least significant digits of the operand. The result address contains the
most significant three digits of the result; the next address word 306, contains
the least significant three digits of the result. The implied decimal points in the
operand and the result are after the LSD and before the MSD respectively.
Figure 3.44
AF4 Reciprocal Function Format After Address Entry
17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 0
Digit 1
(MSD)
Digit 2
Bit No.
Data Address
Digit 2
Digit 5
Result Address
D E
E = Enable Bit (1 = Function in Progress)
D = Done Bit (1 = Function Complete)
MSD = Most Significant Digit
LSD = Least Significant Digit
11512
Digit 3
Digit 3
Digit 1
(MSD)
Digit 4
Digit 6
(LSD)
S = Sign Bit (1 = Negative)
S
S ER
Digit 4 Digit 5
Digit 6
(LSD)
Operand
Result
ER = Error Bit (Illegal Operand, 1 = Input is 0)
200
201
305
306
4. Enter the operand.
You can enter the operand from the keyboard of your industrial terminal or
through ladder diagram functions. Entry of operand 124 yields as its reciprocal
the value .008064 as shown in Figure 3.45.