Rockwell Automation 1772-AF4,D17726.5.3 User Manual, AUX FUNCT PROM - Manual (Page 47)

Programming
Chapter 3
3Ć39
4. Enter the operand.
You can enter the operand from the keyboard of your industrial terminal or
through ladder diagram functions. Entry of an operand (exponent) of e) of 9.42
yields an exponential function value of 1.23(10)
004 . The base r resides in word
305 and the exponent of ten resides in word 306 as shown in Figure 3.37.
Figure 3.37
AF4 Exponential Function Format After Execution
17 16 15 14 13 12 11 10 7 6 5 4 3 2 1 0 Bit No.
Data Address Operand
Result Address Result Base r
D E
E = Enable Bit (1 = Function in Progress)
D = Done Bit (1 = Function Complete) 11506
S = Sign Bit (1 = Negative)
S
S s (Power of 10)
200
305
306
(0)
(0) (1)
(0)
9 4 2
1 2 3
0 0 4
Entry and Display of Input and Result Values
Figure 3.38 shows one method for inserting input values and displaying input
values and results of an AF4 exponential function. Although there are several
techniques for accomplishing this, we chose get instructions. The first rung
requests execution of an AF4 exponential function. The second rung contains
9.42, the exponent of e in word 200 with an implied decimal point after the first
digit. It also shows the result, (1.23)(10)
004 , in the form of 123 in word 305 and
004 in word 206. The decimal points are implied.
Figure 3.38
AF4 Exponential Function Input and Result Display Rungs
201
648
G
305
647
G
306
389
G
Bit
Storage
Execute Aux
Function
Function Number:
Data Addr:
Result Addr:
305
32