User Manual, AUX FUNCT PROM Manual

Programming
Chapter 3
336
If we enter a data address of 201 and a result address of 305, the AF4
establishes the data table format shown in Figure 3.32. The data address
eventually contains the operand. The result address (word 305) contains the first
three digits of the result and word 306 contains the last three digits.
Figure 3.32
AF4 Natural Log Function Format After Address Entry
171615141312111076543210
Digit 1
(MSD)
Digit 2
Bit No.
Data Address
Digit 2
Operand
Digit 5
Result Address
Result
DE
E = Enable Bit (1 = Function in Progress)
D = Done Bit (1 = Function Complete)
MSD = Most Significant Digit
LSD = Least Significant Digit
11502
Digit 3
(LSD)
Digit 3
Digit 1
(MSD)
Digit 4
Digit 6
(LSD)
ER = Error Bit (1 = Input is 0)
ER
201
305
306
4. Enter the number for the operand.
You can enter this number from the keyboard of your industrial terminal or
through ladder diagram functions. Entry of operand = 648 produces the result
6.47389 when the natural log function executes. Figure 3.33 shows how the
result is stored.
Figure 3.33
AF4
Natural Log Function Format After Execution
171615141312111076543210Bit No.
Data Address
Operand
Result Address
Result
DE
E = Enable Bit (1 = Function in Progress)
D = Done Bit (1 = Function Complete)
11503
ER = Illegal Operand (1 = Input is 0)
ER
201
305
306
(0) (1) (0)
64 8
64 7
38 9